Geoff Rubin

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Scholarly Contributions

Books

• Saini, S., Rubin, G., & Kalra, M. (2006). MDCT: A practical approach. doi:10.1007/88-470-0413-6
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  Computed tomography (CT) is the most rapidly evolving medical imaging technology. This book describes current examination techniques and advanced clinical applications of state-of-the-art multidetector computed tomography (MDCT) scanners in chapters contributed by several distinguished radiologists and clinicians. Each chapter is written from a practical perspective so that radiologists, residents, medical physicists, and radiology technologists can obtain relevant information about MDCT applications in neuroradiology, cardiac imaging, chest, abdominal, and musculoskeletal radiology subspecialties. Each coauthor provides pertinent illustrations and tables for better understanding of current and advanced applications of MDCT scanners. Readers will benefit from the experience these authors describe in chapters on MDCT technology, contrast administration techniques, contrast adverse effects and their management, and advanced applications of MDCT. © Springer-Verlag Italia 2006.

Journals/Publications

• Hanneman, K., Playford, D., Dey, D., van Assen, M., Mastrodicasa, D., Cook, T. S., Gichoya, J. W., Williamson, E. E., Rubin, G. D., & , A. H. (2024). Value Creation Through Artificial Intelligence and Cardiovascular Imaging: A Scientific Statement From the American Heart Association. Circulation, 149(6), e296-e311.
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  Multiple applications for machine learning and artificial intelligence (AI) in cardiovascular imaging are being proposed and developed. However, the processes involved in implementing AI in cardiovascular imaging are highly diverse, varying by imaging modality, patient subtype, features to be extracted and analyzed, and clinical application. This article establishes a framework that defines value from an organizational perspective, followed by value chain analysis to identify the activities in which AI might produce the greatest incremental value creation. The various perspectives that should be considered are highlighted, including clinicians, imagers, hospitals, patients, and payers. Integrating the perspectives of all health care stakeholders is critical for creating value and ensuring the successful deployment of AI tools in a real-world setting. Different AI tools are summarized, along with the unique aspects of AI applications to various cardiac imaging modalities, including cardiac computed tomography, magnetic resonance imaging, and positron emission tomography. AI is applicable and has the potential to add value to cardiovascular imaging at every step along the patient journey, from selecting the more appropriate test to optimizing image acquisition and analysis, interpreting the results for classification and diagnosis, and predicting the risk for major adverse cardiac events.
• Cury, R. C., Abbara, S., Achenbach, S., Agatston, A., Berman, D. S., Budoff, M. J., Dill, K. E., Jacobs, J. E., Maroules, C. D., Rubin, G. D., Rybicki, F. J., Schoepf, U. J., Shaw, L. J., Stillman, A. E., White, C. S., Woodard, P. K., & Leipsic, J. A. (2022). CAD-RADS(TM) Coronary Artery Disease - Reporting and Data System. An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR) and the North American Society for Cardiovascular Imaging (NASCI). Endorsed by the American College of Cardiology. Journal of cardiovascular computed tomography, 10(4), 269-81.
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  The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care.
• Cury, R. C., Blankstein, R., Leipsic, J., Abbara, S., Achenbach, S., Berman, D., Bittencourt, M., Budoff, M., Chinnaiyan, K., Choi, A. D., Ghoshhajra, B., Jacobs, J., Koweek, L., Lesser, J., Maroules, C., Rubin, G. D., Rybicki, F. J., Shaw, L. J., Williams, M. C., , Williamson, E., et al. (2022). CAD-RADS™ 2.0 - 2022 Coronary Artery Disease - Reporting and Data System an expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Cardiology (ACC), the American College of Radiology (ACR) and the North America society of cardiovascular imaging (NASCI). Journal of cardiovascular computed tomography.
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  Coronary Artery Disease Reporting and Data System (CAD-RADS) was created to standardize reporting system for patients undergoing coronary CT angiography (CCTA) and to guide possible next steps in patient management. The goal of this updated 2022 CAD-RADS 2.0 is to improve the initial reporting system for CCTA by considering new technical developments in Cardiac CT, including data from recent clinical trials and new clinical guidelines. The updated CAD-RADS classification will follow an established framework of stenosis, plaque burden, and modifiers, which will include assessment of lesion-specific ischemia using CT fractional-flow-reserve (CT-FFR) or myocardial CT perfusion (CTP), when performed. Similar to the method used in the original CAD-RADS version, the determinant for stenosis severity classification will be the most severe coronary artery luminal stenosis on a per-patient basis, ranging from CAD-RADS 0 (zero) for absence of any plaque or stenosis to CAD-RADS 5 indicating the presence of at least one totally occluded coronary artery. Given the increasing data supporting the prognostic relevance of coronary plaque burden, this document will provide various methods to estimate and report total plaque burden. The addition of P1 to P4 descriptors are used to denote increasing categories of plaque burden. The main goal of CAD-RADS, which should always be interpreted together with the impression found in the report, remains to facilitate communication of test results with referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will continue to provide a framework of standardization that may benefit education, research, peer-review, artificial intelligence development, clinical trial design, population health and quality assurance with the ultimate goal of improving patient care.
• Cury, R. C., Leipsic, J., Abbara, S., Achenbach, S., Berman, D., Bittencourt, M., Budoff, M., Chinnaiyan, K., Choi, A. D., Ghoshhajra, B., Jacobs, J., Koweek, L., Lesser, J., Maroules, C., Rubin, G. D., Rybicki, F. J., Shaw, L. J., Williams, M. C., Williamson, E., , White, C. S., et al. (2022). CAD-RADS™ 2.0 - 2022 Coronary Artery Disease - Reporting and Data System An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Cardiology (ACC), the American College of Radiology (ACR) and the North America Society of Cardiovascular Imaging (NASCI). Radiology. Cardiothoracic imaging, 4(5), e220183.
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  Coronary Artery Disease Reporting and Data System (CAD-RADS) was created to standardize reporting system for patients undergoing coronary CT angiography (CCTA) and to guide possible next steps in patient management. The goal of this updated 2022 CAD-RADS 2.0 is to improve the initial reporting system for CCTA by considering new technical developments in Cardiac CT, including data from recent clinical trials and new clinical guidelines. The updated CAD-RADS classification will follow an established framework of stenosis, plaque burden, and modifiers, which will include assessment of lesion-specific ischemia using CT fractional-flow-reserve (CT-FFR) or myocardial CT perfusion (CTP), when performed. Similar to the method used in the original CAD-RADS version, the determinant for stenosis severity classification will be the most severe coronary artery luminal stenosis on a per-patient basis, ranging from CAD-RADS 0 (zero) for absence of any plaque or stenosis to CAD-RADS 5 indicating the presence of at least one totally occluded coronary artery. Given the increasing data supporting the prognostic relevance of coronary plaque burden, this document will provide various methods to estimate and report total plaque burden. The addition of P1 to P4 descriptors are used to denote increasing categories of plaque burden. The main goal of CAD-RADS, which should always be interpreted together with the impression found in the report, remains to facilitate communication of test results with referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will continue to provide a framework of standardization that may benefit education, research, peer-review, artificial intelligence development, clinical trial design, population health and quality assurance with the ultimate goal of improving patient care. Coronary Artery Disease, Coronary CTA, CAD-RADS, Reporting and Data System, Stenosis Severity, Report Standardization Terminology, Plaque Burden, Ischemia This article is published synchronously in , and . © 2022 Society of Cardiovascular Computed Tomography. Published by RSNA with permission.
• Cury, R. C., Leipsic, J., Abbara, S., Achenbach, S., Berman, D., Bittencourt, M., Budoff, M., Chinnaiyan, K., Choi, A. D., Ghoshhajra, B., Jacobs, J., Koweek, L., Lesser, J., Maroules, C., Rubin, G. D., Rybicki, F. J., Shaw, L. J., Williams, M. C., Williamson, E., , White, C. S., et al. (2022). CAD-RADS™ 2.0 - 2022 Coronary Artery Disease - Reporting and Data System.: An expert consensus document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Cardiology (ACC), the American College of Radiology (ACR) and the North America Society of Cardiovascular Imaging (NASCI). Journal of the American College of Radiology : JACR, 19(11), 1185-1212.
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  Coronary Artery Disease Reporting and Data System (CAD-RADS) was created to standardize reporting system for patients undergoing coronary CT angiography (CCTA) and to guide possible next steps in patient management. The goal of this updated 2022 CAD-RADS 2.0 is to improve the initial reporting system for CCTA by considering new technical developments in Cardiac CT, including data from recent clinical trials and new clinical guidelines. The updated CAD-RADS classification will follow an established framework of stenosis, plaque burden, and modifiers, which will include assessment of lesion-specific ischemia using CT fractional-flow-reserve (CT-FFR) or myocardial CT perfusion (CTP), when performed. Similar to the method used in the original CAD-RADS version, the determinant for stenosis severity classification will be the most severe coronary artery luminal stenosis on a per-patient basis, ranging from CAD-RADS 0 (zero) for absence of any plaque or stenosis to CAD-RADS 5 indicating the presence of at least one totally occluded coronary artery. Given the increasing data supporting the prognostic relevance of coronary plaque burden, this document will provide various methods to estimate and report total plaque burden. The addition of P1 to P4 descriptors are used to denote increasing categories of plaque burden. The main goal of CAD-RADS, which should always be interpreted together with the impression found in the report, remains to facilitate communication of test results with referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will continue to provide a framework of standardization that may benefit education, research, peer-review, artificial intelligence development, clinical trial design, population health and quality assurance with the ultimate goal of improving patient care.
• Cury, R. C., Leipsic, J., Abbara, S., Achenbach, S., Berman, D., Bittencourt, M., Budoff, M., Chinnaiyan, K., Choi, A. D., Ghoshhajra, B., Jacobs, J., Koweek, L., Lesser, J., Maroules, C., Rubin, G. D., Rybicki, F. J., Shaw, L. J., Williams, M. C., Williamson, E., , White, C. S., et al. (2022). CAD-RADS™ 2.0 - 2022 Coronary Artery Disease-Reporting and Data System: An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Cardiology (ACC), the American College of Radiology (ACR), and the North America Society of Cardiovascular Imaging (NASCI). JACC. Cardiovascular imaging, 15(11), 1974-2001.
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  Coronary Artery Disease Reporting and Data System (CAD-RADS) was created to standardize reporting system for patients undergoing coronary CT angiography (CCTA) and to guide possible next steps in patient management. The goal of this updated 2022 CAD-RADS 2.0 is to improve the initial reporting system for CCTA by considering new technical developments in cardiac CT, including data from recent clinical trials and new clinical guidelines. The updated CAD-RADS classification will follow an established framework of stenosis, plaque burden, and modifiers, which will include assessment of lesion-specific ischemia using CT fractional-flow-reserve (CT-FFR) or myocardial CT perfusion (CTP), when performed. Similar to the method used in the original CAD-RADS version, the determinant for stenosis severity classification will be the most severe coronary artery luminal stenosis on a per-patient basis, ranging from CAD-RADS 0 (zero) for absence of any plaque or stenosis to CAD-RADS 5 indicating the presence of at least one totally occluded coronary artery. Given the increasing data supporting the prognostic relevance of coronary plaque burden, this document will provide various methods to estimate and report total plaque burden. The addition of P1 to P4 descriptors are used to denote increasing categories of plaque burden. The main goal of CAD-RADS, which should always be interpreted together with the impression found in the report, remains to facilitate communication of test results with referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will continue to provide a framework of standardization that may benefit education, research, peer-review, artificial intelligence development, clinical trial design, population health and quality assurance with the ultimate goal of improving patient care.
• D'Anniballe, V. M., Tushar, F. I., Faryna, K., Han, S., Mazurowski, M. A., Rubin, G. D., & Lo, J. Y. (2022). Multi-label annotation of text reports from computed tomography of the chest, abdomen, and pelvis using deep learning. BMC medical informatics and decision making, 22(1), 102.
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  There is progress to be made in building artificially intelligent systems to detect abnormalities that are not only accurate but can handle the true breadth of findings that radiologists encounter in body (chest, abdomen, and pelvis) computed tomography (CT). Currently, the major bottleneck for developing multi-disease classifiers is a lack of manually annotated data. The purpose of this work was to develop high throughput multi-label annotators for body CT reports that can be applied across a variety of abnormalities, organs, and disease states thereby mitigating the need for human annotation.
• Raman, R., Raman, B., Napel, S., & Rubin, G. D. (2022). Improved speed of bone removal in computed tomographic angiography using automated targeted morphological separation: method and evaluation in computed tomographic angiography of lower extremity occlusive disease. Journal of computer assisted tomography, 32(3), 485-91.
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  We developed an automated algorithm for bone removal in computed tomographic angiographic images that identifies and deletes connections between bone and vessels. Our automated algorithm is significantly faster than manual methods (2.45 minutes vs 73 minutes) and only generates about 2 small artifactual deletions per patient, mostly in the region of the ankle. Image quality was equivalent to manual methods. It shows promise as a tool for fast and accurate postprocessing of computed tomographic angiograms.
• Rubin, G. D., Cury, R. C., Leipsic, J., Abbara, S., Achenbach, S., Berman, D., Bittencourt, M., Budoff, M., Chinnaiyan, K., Choi, A. D., Ghoshhajra, B., Jacobs, J., Koweek, L., Lesser, J., Maroules, C., Rybicki, F. J., Shaw, L. J., Williams, M. C., Williamson, E., , White, C. S., et al. (2022). CAD-RADS™ 2.0 – 2022 Coronary Artery Disease – Reporting and Data System An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Cardiology (ACC), the American College of Radiology (ACR) and the North America Society of Cardiovascular Imaging (NASCI). Radiology: Cardiothoracic Imaging, 4(5). doi:10.1148/ryct.220183
• Rubin, G. D., Lo, J. Y., Mazurowski, M. A., Han, S., Faryna, K., Tushar, F. I., & D'Anniballe, V. M. (2022). Multi-label annotation of text reports from computed tomography of the chest, abdomen, and pelvis using deep learning. BMC Medical Informatics and Decision Making. doi:10.1186/s12911-022-01843-4
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  There is progress to be made in building artificially intelligent systems to detect abnormalities that are not only accurate but can handle the true breadth of findings that radiologists encounter in body (chest, abdomen, and pelvis) computed tomography (CT). Currently, the major bottleneck for developing multi-disease classifiers is a lack of manually annotated data. The purpose of this work was to develop high throughput multi-label annotators for body CT reports that can be applied across a variety of abnormalities, organs, and disease states thereby mitigating the need for human annotation.We used a dictionary approach to develop rule-based algorithms (RBA) for extraction of disease labels from radiology text reports. We targeted three organ systems (lungs/pleura, liver/gallbladder, kidneys/ureters) with four diseases per system based on their prevalence in our dataset. To expand the algorithms beyond pre-defined keywords, attention-guided recurrent neural networks (RNN) were trained using the RBA-extracted labels to classify reports as being positive for one or more diseases or normal for each organ system. Alternative effects on disease classification performance were evaluated using random initialization or pre-trained embedding as well as different sizes of training datasets. The RBA was tested on a subset of 2158 manually labeled reports and performance was reported as accuracy and F-score. The RNN was tested against a test set of 48,758 reports labeled by RBA and performance was reported as area under the receiver operating characteristic curve (AUC), with 95% CIs calculated using the DeLong method.Manual validation of the RBA confirmed 91-99% accuracy across the 15 different labels. Our models extracted disease labels from 261,229 radiology reports of 112,501 unique subjects. Pre-trained models outperformed random initialization across all diseases. As the training dataset size was reduced, performance was robust except for a few diseases with a relatively small number of cases. Pre-trained classification AUCs reached > 0.95 for all four disease outcomes and normality across all three organ systems.Our label-extracting pipeline was able to encompass a variety of cases and diseases in body CT reports by generalizing beyond strict rules with exceptional accuracy. The method described can be easily adapted to enable automated labeling of hospital-scale medical data sets for training image-based disease classifiers.
• Taylor, A. J., Cerqueira, M., Hodgson, J. M., Mark, D., Min, J., O'Gara, P., Rubin, G. D., , A. C., , S. o., , A. C., , A. H., , A. S., , A. S., , N. A., , S. f., & , S. f. (2022). ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Journal of cardiovascular computed tomography, 4(6), 407.e1-33.
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  The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research.
• Tushar, F. I., D'Anniballe, V. M., Hou, R., Mazurowski, M. A., Fu, W., Samei, E., Rubin, G. D., & Lo, J. Y. (2022). Classification of Multiple Diseases on Body CT Scans Using Weakly Supervised Deep Learning. Radiology. Artificial intelligence, 4(1), e210026.
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  To design multidisease classifiers for body CT scans for three different organ systems using automatically extracted labels from radiology text reports.
• Won, J. H., Rubin, G. D., & Napel, S. (2022). Flattening the abdominal aortic tree for effective visualization. Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2006, 3345-8.
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  We developed a novel visualization method for providing an uncluttered view of the abdominal aorta and its branches. The method abstracts the complex geometry of vessels using a convex primitive, and uses a sweep line algorithm to find a suboptimal placement of the primitive. The method was evaluated using 10 CT angiography datasets and resulted in a clear visualization with all cluttering intersections removed. The method can be used to convey clinical findings, including lumen patency and lesion locations, in a single two-dimensional image.
• Zimmerman, M. E., Batlle, J. C., Biga, C., Blankstein, R., Ghoshhajra, B. B., Rabbat, M. G., Wesbey, G. E., & Rubin, G. D. (2022). The direct costs of coronary CT angiography relative to contrast-enhanced thoracic CT: Time-driven activity-based costing. Journal of cardiovascular computed tomography, 15(6), 477-483.
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  Coronary CT angiography (CCTA) and contrast-enhanced thoracic CT (CECT) are distinctly different diagnostic procedures that involve intravenous contrast-enhanced CT of the chest. The technical component of these procedures is reimbursed at the same rate by the Centers for Medicare and Medicaid Services (CMS). This study tests the hypothesis that the direct costs of performing these exams are significantly different.
• Draelos, R. L., Dov, D., Mazurowski, M. A., Lo, J. Y., Henao, R., Rubin, G. D., & Carin, L. (2021). Machine-learning-based multiple abnormality prediction with large-scale chest computed tomography volumes. Medical image analysis, 67, 101857.
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  Machine learning models for radiology benefit from large-scale data sets with high quality labels for abnormalities. We curated and analyzed a chest computed tomography (CT) data set of 36,316 volumes from 19,993 unique patients. This is the largest multiply-annotated volumetric medical imaging data set reported. To annotate this data set, we developed a rule-based method for automatically extracting abnormality labels from free-text radiology reports with an average F-score of 0.976 (min 0.941, max 1.0). We also developed a model for multi-organ, multi-disease classification of chest CT volumes that uses a deep convolutional neural network (CNN). This model reached a classification performance of AUROC >0.90 for 18 abnormalities, with an average AUROC of 0.773 for all 83 abnormalities, demonstrating the feasibility of learning from unfiltered whole volume CT data. We show that training on more labels improves performance significantly: for a subset of 9 labels - nodule, opacity, atelectasis, pleural effusion, consolidation, mass, pericardial effusion, cardiomegaly, and pneumothorax - the model's average AUROC increased by 10% when the number of training labels was increased from 9 to all 83. All code for volume preprocessing, automated label extraction, and the volume abnormality prediction model is publicly available. The 36,316 CT volumes and labels will also be made publicly available pending institutional approval.
• Johkoh, T., Lee, K. S., Nishino, M., Travis, W. D., Ryu, J. H., Lee, H. Y., Ryerson, C. J., Franquet, T., Bankier, A. A., Brown, K. K., Goo, J. M., Kauczor, H. U., Lynch, D. A., Nicholson, A. G., Richeldi, L., Schaefer-Prokop, C. M., Verschakelen, J., Raoof, S., Rubin, G. D., , Powell, C., et al. (2021). Chest CT Diagnosis and Clinical Management of Drug-Related Pneumonitis in Patients Receiving Molecular Targeting Agents and Immune Checkpoint Inhibitors: A Position Paper From the Fleischner Society. Chest, 159(3), 1107-1125.
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  Use of molecular targeting agents and immune checkpoint inhibitors (ICIs) has increased the frequency and broadened the spectrum of lung toxicity, particularly in patients with cancer. The diagnosis of drug-related pneumonitis (DRP) is usually achieved by excluding other potential known causes. Awareness of the incidence and risk factors for DRP is becoming increasingly important. The severity of symptoms associated with DRP may range from mild or none to life-threatening with rapid progression to death. Imaging features of DRP should be assessed in consideration of the distribution of lung parenchymal abnormalities (radiologic pattern approach). The CT patterns reflect acute (diffuse alveolar damage) interstitial pneumonia and transient (simple pulmonary eosinophilia) lung abnormality, subacute interstitial disease (organizing pneumonia and hypersensitivity pneumonitis), and chronic interstitial disease (nonspecific interstitial pneumonia). A single drug can be associated with multiple radiologic patterns. Treatment of a patient suspected of having DRP generally consists of drug discontinuation, immunosuppressive therapy, or both, along with supportive measures eventually including supplemental oxygen and intensive care. In this position paper, the authors provide diagnostic criteria and management recommendations for DRP that should be of interest to radiologists, clinicians, clinical trialists, and trial sponsors, among others.
• Johkoh, T., Lee, K. S., Nishino, M., Travis, W. D., Ryu, J. H., Lee, H. Y., Ryerson, C. J., Franquet, T., Bankier, A. A., Brown, K. K., Goo, J. M., Kauczor, H. U., Lynch, D. A., Nicholson, A. G., Richeldi, L., Schaefer-Prokop, C. M., Verschakelen, J., Raoof, S., Rubin, G. D., , Powell, C., et al. (2021). Chest CT Diagnosis and Clinical Management of Drug-related Pneumonitis in Patients Receiving Molecular Targeting Agents and Immune Checkpoint Inhibitors: A Position Paper from the Fleischner Society. Radiology, 298(3), 550-566.
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  Use of molecular targeting agents and immune checkpoint inhibitors (ICIs) has increased the frequency and broadened the spectrum of lung toxicity, particularly in patients with cancer. The diagnosis of drug-related pneumonitis (DRP) is usually achieved by excluding other potential known causes. Awareness of the incidence and risk factors for DRP is becoming increasingly important. The severity of symptoms associated with DRP may range from mild or none to life-threatening with rapid progression to death. Imaging features of DRP should be assessed in consideration of the distribution of lung parenchymal abnormalities (radiologic pattern approach). The CT patterns reflect acute (diffuse alveolar damage) interstitial pneumonia and transient (simple pulmonary eosinophilia) lung abnormality, subacute interstitial disease (organizing pneumonia and hypersensitivity pneumonitis), and chronic interstitial disease (nonspecific interstitial pneumonia). A single drug can be associated with multiple radiologic patterns. Treatment of a patient suspected of having DRP generally consists of drug discontinuation, immunosuppressive therapy, or both, along with supportive measures eventually including supplemental oxygen and intensive care. In this position paper, the authors provide diagnostic criteria and management recommendations for DRP that should be of interest to radiologists, clinicians, clinical trialists, and trial sponsors, among others. This article is a simultaneous joint publication in and . The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. Published under a CC BY 4.0 license.
• Kanne, J. P., Bai, H., Bernheim, A., Chung, M., Haramati, L. B., Kallmes, D. F., Little, B. P., Rubin, G. D., & Sverzellati, N. (2021). COVID-19 Imaging: What We Know Now and What Remains Unknown. Radiology, 299(3), E262-E279.
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  Infection with SARS-CoV-2 ranges from an asymptomatic condition to a severe and sometimes fatal disease, with mortality most frequently being the result of acute lung injury. The role of imaging has evolved during the pandemic, with CT initially being an alternative and possibly superior testing method compared with reverse transcriptase-polymerase chain reaction (RT-PCR) testing and evolving to having a more limited role based on specific indications. Several classification and reporting schemes were developed for chest imaging early during the pandemic for patients suspected of having COVID-19 to aid in triage when the availability of RT-PCR testing was limited and its level of performance was unclear. Interobserver agreement for categories with findings typical of COVID-19 and those suggesting an alternative diagnosis is high across multiple studies. Furthermore, some studies looking at the extent of lung involvement on chest radiographs and CT images showed correlations with critical illness and a need for mechanical ventilation. In addition to pulmonary manifestations, cardiovascular complications such as thromboembolism and myocarditis have been ascribed to COVID-19, sometimes contributing to neurologic and abdominal manifestations. Finally, artificial intelligence has shown promise for use in determining both the diagnosis and prognosis of COVID-19 pneumonia with respect to both radiography and CT.
• Remy-Jardin, M., Ryerson, C. J., Schiebler, M. L., Leung, A. N., Wild, J. M., Hoeper, M. M., Alderson, P. O., Goodman, L. R., Mayo, J., Haramati, L. B., Ohno, Y., Thistlethwaite, P., van Beek, E. J., Knight, S. L., Lynch, D. A., Rubin, G. D., & Humbert, M. (2021). Imaging of Pulmonary Hypertension in Adults: A Position Paper from the Fleischner Society. Radiology, 298(3), 531-549.
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  Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mm Hg and classified into five different groups sharing similar pathophysiologic mechanisms, hemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: Is noninvasive imaging capable of identifying PH? What is the role of imaging in establishing the cause of PH? How does imaging determine the severity and complications of PH? How should imaging be used to assess chronic thromboembolic PH before treatment? Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH. This article is a simultaneous joint publication in and . The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. © 2021 RSNA and the European Respiratory Society.
• Remy-Jardin, M., Ryerson, C. J., Schiebler, M. L., Leung, A. N., Wild, J. M., Hoeper, M. M., Alderson, P. O., Goodman, L. R., Mayo, J., Haramati, L. B., Ohno, Y., Thistlethwaite, P., van Beek, E. J., Knight, S. L., Lynch, D. A., Rubin, G. D., & Humbert, M. (2021). Imaging of pulmonary hypertension in adults: a position paper from the Fleischner Society. The European respiratory journal, 57(1).
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  Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mmHg and classified into five different groups sharing similar pathophysiologic mechanisms, haemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: Is noninvasive imaging capable of identifying PH? What is the role of imaging in establishing the cause of PH? How does imaging determine the severity and complications of PH? How should imaging be used to assess chronic thromboembolic PH before treatment? Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH.
• Rubin, G. D. (2021). CT Diagnosis of COVID-19: A View through the PICOTS Lens. Radiology, 301(1), E375-E377.
• Rubin, G. D. (2021). CT Diagnosis of COVID-19: A View through the PICOTS Lens. Radiology, 301(1), E375-E377. doi:10.1148/radiol.2021211454
• Samei, E., Richards, T., Segars, W. P., Daubert, M. A., Ivanov, A., Rubin, G. D., Douglas, P. S., & Hoffmann, U. (2021). Task-dependent estimability index to assess the quality of cardiac computed tomography angiography for quantifying coronary stenosis. Journal of medical imaging (Bellingham, Wash.), 8(1), 013501.
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  Quantifying stenosis in cardiac computed tomography angiography (CTA) images remains a difficult task, as image noise and cardiac motion can degrade image quality and distort underlying anatomic information. The purpose of this study was to develop a computational framework to objectively assess the precision of quantifying coronary stenosis in cardiac CTA. The framework used models of coronary vessels and plaques, asymmetric motion point spread functions, CT image blur (task-based modulation transfer functions) and noise (noise-power spectrums), and an automated maximum-likelihood estimator implemented as a matched template squared-difference operator. These factors were integrated into an estimability index ( ) as a task-based measure of image quality in cardiac CTA. The index was applied to assess how well it can to predict the quality of 132 clinical cases selected from the Prospective Multicenter Imaging Study for Evaluation of Chest Pain trial. The cases were divided into two cohorts, high quality and low quality, based on clinical scores and the concordance of clinical evaluations of cases by experienced cardiac imagers. The framework was also used to ascertain protocol factors for CTA Biomarker initiative of the Quantitative Imaging Biomarker Alliance (QIBA). The index categorized the patient datasets with an area under the curve of 0.985, an accuracy of 0.977, and an optimal threshold of 25.58 corresponding to a stenosis estimation precision (standard deviation) of 3.91%. Data resampling and training-test validation methods demonstrated stable classifier thresholds and receiver operating curve performance. The framework was successfully applicable to the QIBA objective. A computational framework to objectively quantify stenosis estimation task performance was successfully implemented and was reflective of clinical results in the context of a prominent clinical trial with diverse sites, readers, scanners, acquisition protocols, and patients. It also demonstrated the potential for prospective optimization of imaging protocols toward targeted precision and measurement consistency in cardiac CT images.
• Li, B., Smith, T. B., Choudhury, K. R., Harrawood, B., Ebner, L., Roos, J. E., & Rubin, G. D. (2020). Influence of background lung characteristics on nodule detection with computed tomography. Journal of medical imaging (Bellingham, Wash.), 7(2), 022409.
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  We sought to characterize local lung complexity in chest computed tomography (CT) and to characterize its impact on the detectability of pulmonary nodules. Forty volumetric chest CT scans were created by embedding between three and five simulated 5-mm lung nodules into one of three volumetric chest CT datasets. Thirteen radiologists evaluated 157 nodules, resulting in 2041 detection opportunities. Analyzing the substrate CT data prior to nodule insertion, 14 image features were measured within a region around each nodule location. A generalized linear mixed-effects statistical model was fit to the data to verify the contribution of each metric on detectability. The model was tuned for simplicity, interpretability, and generalizability using stepwise regression applied to the primary features and their interactions. We found that variables corresponding to each of five categories (local structural distractors, local intensity, global context, local vascularity, and contiguity with structural distractors) were significant ( ) factors in a standardized model. Moreover, reader-specific models conveyed significant differences among readers with significant distraction (missed detections) influenced by local intensity- versus local-structural characteristics being mutually exclusive. Readers with significant local intensity distraction ( ) detected substantially fewer lung nodules than those who were significantly distracted by local structure ( ), 46.1% versus 65.3% mean nodules detected, respectively.
• Rubin, G. D., Ryerson, C. J., Haramati, L. B., Sverzellati, N., Kanne, J. P., Raoof, S., Schluger, N. W., Volpi, A., Yim, J. J., Martin, I. B., Anderson, D. J., Kong, C., Altes, T., Bush, A., Desai, S. R., Goldin, J., Goo, J. M., Humbert, M., Inoue, Y., , Kauczor, H. U., et al. (2020). The Role of Chest Imaging in Patient Management During the COVID-19 Pandemic: A Multinational Consensus Statement From the Fleischner Society. Chest, 158(1), 106-116.
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  With more than 900,000 confirmed cases worldwide and nearly 50,000 deaths during the first 3 months of 2020, the coronavirus disease 2019 (COVID-19) pandemic has emerged as an unprecedented health care crisis. The spread of COVID-19 has been heterogeneous, resulting in some regions having sporadic transmission and relatively few hospitalized patients with COVID-19 and others having community transmission that has led to overwhelming numbers of severe cases. For these regions, health care delivery has been disrupted and compromised by critical resource constraints in diagnostic testing, hospital beds, ventilators, and health care workers who have fallen ill to the virus exacerbated by shortages of personal protective equipment. Although mild cases mimic common upper respiratory viral infections, respiratory dysfunction becomes the principal source of morbidity and mortality as the disease advances. Thoracic imaging with chest radiography and CT are key tools for pulmonary disease diagnosis and management, but their role in the management of COVID-19 has not been considered within the multivariable context of the severity of respiratory disease, pretest probability, risk factors for disease progression, and critical resource constraints. To address this deficit, a multidisciplinary panel comprised principally of radiologists and pulmonologists from 10 countries with experience managing patients with COVID-19 across a spectrum of health care environments evaluated the utility of imaging within three scenarios representing varying risk factors, community conditions, and resource constraints. Fourteen key questions, corresponding to 11 decision points within the three scenarios and three additional clinical situations, were rated by the panel based on the anticipated value of the information that thoracic imaging would be expected to provide. The results were aggregated, resulting in five main and three additional recommendations intended to guide medical practitioners in the use of chest radiography and CT in the management of COVID-19.
• Rubin, G. D., Ryerson, C. J., Haramati, L. B., Sverzellati, N., Kanne, J. P., Raoof, S., Schluger, N. W., Volpi, A., Yim, J. J., Martin, I. B., Anderson, D. J., Kong, C., Altes, T., Bush, A., Desai, S. R., Goldin, O., Goo, J. M., Humbert, M., Inoue, Y., , Kauczor, H. U., et al. (2020). The Role of Chest Imaging in Patient Management during the COVID-19 Pandemic: A Multinational Consensus Statement from the Fleischner Society. Radiology, 296(1), 172-180.
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  With more than 900 000 confirmed cases worldwide and nearly 50 000 deaths during the first 3 months of 2020, the coronavirus disease 2019 (COVID-19) pandemic has emerged as an unprecedented health care crisis. The spread of COVID-19 has been heterogeneous, resulting in some regions having sporadic transmission and relatively few hospitalized patients with COVID-19 and others having community transmission that has led to overwhelming numbers of severe cases. For these regions, health care delivery has been disrupted and compromised by critical resource constraints in diagnostic testing, hospital beds, ventilators, and health care workers who have fallen ill to the virus exacerbated by shortages of personal protective equipment. Although mild cases mimic common upper respiratory viral infections, respiratory dysfunction becomes the principal source of morbidity and mortality as the disease advances. Thoracic imaging with chest radiography and CT are key tools for pulmonary disease diagnosis and management, but their role in the management of COVID-19 has not been considered within the multivariable context of the severity of respiratory disease, pretest probability, risk factors for disease progression, and critical resource constraints. To address this deficit, a multidisciplinary panel comprised principally of radiologists and pulmonologists from 10 countries with experience managing patients with COVID-19 across a spectrum of health care environments evaluated the utility of imaging within three scenarios representing varying risk factors, community conditions, and resource constraints. Fourteen key questions, corresponding to 11 decision points within the three scenarios and three additional clinical situations, were rated by the panel based on the anticipated value of the information that thoracic imaging would be expected to provide. The results were aggregated, resulting in five main and three additional recommendations intended to guide medical practitioners in the use of chest radiography and CT in the management of COVID-19.
• Tailor, T. D., Tong, B. C., Gao, J., Henderson, L. M., Choudhury, K. R., & Rubin, G. D. (2020). Utilization of Lung Cancer Screening in the Medicare Fee-for-Service Population. Chest, 158(5), 2200-2210.
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  A number of organizations, including the US Preventive Services Task Force (USPSTF), recommend lung cancer screening (LCS) with low-dose CT (LDCT) imaging for high-risk current and former smokers. In 2015, Medicare issued a decision to cover LCS as a preventive health benefit; however, utilization by the Medicare population has not been thoroughly examined.
• White, C. S., & Rubin, G. D. (2020). The Puzzle of the Perifissural Nodule. Radiology. Cardiothoracic imaging, 2(4), e200409.
• Tailor, T. D., Choudhury, K. R., Tong, B. C., Christensen, J. D., Sosa, J. A., & Rubin, G. D. (2019). Geographic Access to CT for Lung Cancer Screening: A Census Tract-Level Analysis of Cigarette Smoking in the United States and Driving Distance to a CT Facility. Journal of the American College of Radiology : JACR, 16(1), 15-23.
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  Spatial access to health care resources is a requisite for utilization. Our purpose was to determine, at a census tract level, the geographic distribution of US smokers and their driving distance to an ACR-accredited CT facility.
• Tailor, T. D., Tong, B. C., Gao, J., Choudhury, K. R., & Rubin, G. D. (2019). A Geospatial Analysis of Factors Affecting Access to CT Facilities: Implications for Lung Cancer Screening. Journal of the American College of Radiology : JACR, 16(12), 1663-1668.
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  The association between access to CT facilities for lung cancer screening and population characteristics is understudied. We aimed to determine the relationship between census tract-level socioeconomic characteristics (SEC) and driving distance to an ACR-accredited CT facility.
• , W. C., Hirshfeld, J. W., Ferrari, V. A., Bengel, F. M., Bergersen, L., Chambers, C. E., Einstein, A. J., Eisenberg, M. J., Fogel, M. A., Gerber, T. C., Haines, D. E., Laskey, W. K., Limacher, M. C., Nichols, K. J., Pryma, D. A., Raff, G. L., Rubin, G. D., Smith, D., Stillman, A. E., , Thomas, S. A., et al. (2018). 2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging-Best Practices for Safety and Effectiveness, Part 1: Radiation Physics and Radiation Biology: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways Developed in Collaboration With Mended Hearts. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions, 92(2), 203-221.
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  The stimulus to create this document was the recognition that ionizing radiation-guided cardiovascular procedures are being performed with increasing frequency, leading to greater patient radiation exposure and, potentially, to greater exposure for clinical personnel. Although the clinical benefit of these procedures is substantial, there is concern about the implications of medical radiation exposure. The American College of Cardiology leadership concluded that it is important to provide practitioners with an educational resource that assembles and interprets the current radiation knowledge base relevant to cardiovascular procedures. By applying this knowledge base, cardiovascular practitioners will be able to select procedures optimally, and minimize radiation exposure to patients and to clinical personnel. Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness is a comprehensive overview of ionizing radiation use in cardiovascular procedures and is published online. To provide the most value to our members, we divided the print version of this document into 2 focused parts. Part I: Radiation Physics and Radiation Biology addresses the issue of medical radiation exposure, the basics of radiation physics and dosimetry, and the basics of radiation biology and radiation-induced adverse effects. Part II: Radiological Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection covers the basics of operation and radiation delivery for the 3 cardiovascular imaging modalities (x-ray fluoroscopy, x-ray computed tomography, and nuclear scintigraphy) and will be published in the next issue of the Journal.
• , W. C., Hirshfeld, J. W., Ferrari, V. A., Bengel, F. M., Bergersen, L., Chambers, C. E., Einstein, A. J., Eisenberg, M. J., Fogel, M. A., Gerber, T. C., Haines, D. E., Laskey, W. K., Limacher, M. C., Nichols, K. J., Pryma, D. A., Raff, G. L., Rubin, G. D., Smith, D., Stillman, A. E., , Thomas, S. A., et al. (2018). 2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging-Best Practices for Safety and Effectiveness, Part 2: Radiological Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions, 92(2), 222-246.
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  The stimulus to create this document was the recognition that ionizing radiation-guided cardiovascular procedures are being performed with increasing frequency, leading to greater patient radiation exposure and, potentially, to greater exposure to clinical personnel. While the clinical benefit of these procedures is substantial, there is concern about the implications of medical radiation exposure. ACC leadership concluded that it is important to provide practitioners with an educational resource that assembles and interprets the current radiation knowledge base relevant to cardiovascular procedures. By applying this knowledge base, cardiovascular practitioners will be able to select procedures optimally, and minimize radiation exposure to patients and to clinical personnel. "Optimal Use of Ionizing Radiation in Cardiovascular Imaging - Best Practices for Safety and Effectiveness" is a comprehensive overview of ionizing radiation use in cardiovascular procedures and is published online. To provide the most value to our members, we divided the print version of this document into 2 focused parts. "Part I: Radiation Physics and Radiation Biology" addresses radiation physics, dosimetry and detrimental biologic effects. "Part II: Radiologic Equipment Operation, Dose-Sparing Methodologies, Patient and Medical Personnel Protection" covers the basics of operation and radiation delivery for the 3 cardiovascular imaging modalities (x-ray fluoroscopy, x-ray computed tomography, and nuclear scintigraphy). For each modality, it includes the determinants of radiation exposure and techniques to minimize exposure to both patients and to medical personnel.
• , W. C., Hirshfeld, J. W., Ferrari, V. A., Bengel, F. M., Bergersen, L., Chambers, C. E., Einstein, A. J., Eisenberg, M. J., Fogel, M. A., Gerber, T. C., Haines, D. E., Laskey, W. K., Limacher, M. C., Nichols, K. J., Pryma, D. A., Raff, G. L., Rubin, G. D., Smith, D., Stillman, A. E., , Thomas, S. A., et al. (2018). 2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions, 92(2), E35-E97.
• Hirshfeld, J. W., Ferrari, V. A., Bengel, F. M., Bergersen, L., Chambers, C. E., Einstein, A. J., Eisenberg, M. J., Fogel, M. A., Gerber, T. C., Haines, D. E., Laskey, W. K., Limacher, M. C., Hirshfeld, J. W., Nichols, K. J., Ferrari, V. A., Pryma, D. A., Bengel, F. M., Raff, G. L., Bergersen, L., , Rubin, G. D., et al. (2018). 2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging-Best Practices for Safety and Effectiveness, Part 1: Radiation Physics and Radiation Biology: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways. Journal of the American College of Cardiology, 71(24), 2811-2828.
• Hirshfeld, J. W., Ferrari, V. A., Bengel, F. M., Bergersen, L., Chambers, C. E., Einstein, A. J., Eisenberg, M. J., Fogel, M. A., Gerber, T. C., Haines, D. E., Laskey, W. K., Limacher, M. C., Nichols, K. J., Pryma, D. A., Raff, G. L., Rubin, G. D., Smith, D., Stillman, A. E., Thomas, S. A., , Tsai, T. T., et al. (2018). 2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness: A Report of the American College of Cardiology Task Force on Expert Consensus Decision Pathways. Journal of the American College of Cardiology, 71(24), e283-e351.
• Richards, T., Sturgeon, G. M., Ramirez-Giraldo, J. C., Rubin, G. D., Koweek, L. H., Segars, W. P., & Samei, E. (2018). Quantification of uncertainty in the assessment of coronary plaque in CCTA through a dynamic cardiac phantom and 3D-printed plaque model. Journal of medical imaging (Bellingham, Wash.), 5(1), 013501.
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  The purpose of this study was to develop a dynamic physical cardiac phantom with a realistic coronary plaque to investigate stenosis measurement accuracy under clinically relevant heart-rates. The coronary plaque model (5 mm diameter, 50% stenosis, and 32 mm long) was designed and 3D-printed with tissue equivalent materials (calcified plaque with iodine-enhanced lumen). Realistic cardiac motion was modeled by converting computational cardiac motion vectors into compression and rotation profiles executed by a commercial base cardiac phantom. The phantom was imaged on a dual-source CT system applying a retrospective gated coronary CT angiography (CCTA) protocol using synthesized motion-synchronized electrocardiogram (ECG) waveforms. Multiplanar reformatted images were reconstructed along vessel centerlines. Enhanced lumens were segmented by five independent operators. On average, stenosis measurement accuracy was 0.9% positively biased for the motion-free condition. Average measurement accuracy monotonically decreased from 0.9% positive bias for the motion-free condition to 18.5% negative bias at 90 beats per minute. Contrast-to-noise ratio, lumen circularity, and segmentation conformity also decreased monotonically with increasing heart-rate. These results demonstrate successful implementation of a base cardiac phantom with a 3D-printed coronary plaque model, relevant motion profile, and coordinated ECG waveform. They further show the utility of the model to ascertain metrics of CCTA accuracy and image quality under realistic plaque, motion, and acquisition conditions.
• Rubin, G. D., & Abramson, R. G. (2018). Creating Value through Incremental Innovation: Managing Culture, Structure, and Process. Radiology, 288(2), 330-340.
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  While the looming threat of large-scale disruptive innovation consumes disproportionate attention, incremental innovation remains an important tool for preserving and growing radiology practices within a dynamic marketplace. Incremental innovation, defined as the process of making improvements or additions to an organization while maintaining the organization's core product or service model, is accessible to practices of all sizes and must not be overlooked if practices are to maintain their competitive advantage. This article explores cultural, structural, and process enablers for incremental innovation. Successful innovation cultures foster the ability to import and exploit external knowledge (adaptive capacity), encourage creative thought from all levels of the organization, display sensitivity toward the competency-destroying potential of certain changes, cultivate a positive perceptual bias toward organizational threats, and build tolerance for risk and uncertainty when prototyping new ideas. Structural elements promoting incremental innovation include dedicated resources for innovation planning, flexible and organic team structures, strong centralized governance models, robust communication systems, and organizational incentives encouraging exploration of new concepts. Processes important to innovation include periodic environmental scanning, strategic and scenario planning, use of an objectively gated system for testing and filtering new ideas, and use of an approach to implementation that emphasizes empowerment of project managers, removal of barriers, and proactive communication around change.
• Smith, T. B., Rubin, G. D., Solomon, J., Harrawood, B., Choudhury, K. R., & Samei, E. (2018). Local complexity metrics to quantify the effect of anatomical noise on detectability of lung nodules in chest CT imaging. Journal of medical imaging (Bellingham, Wash.), 5(4), 045502.
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  The purpose of this study is to (1) develop metrics to characterize the regional anatomical complexity of the lungs, and (2) relate these metrics with lung nodule detection in chest CT. A free-scrolling reader-study with virtually inserted nodules (13 radiologists × 157 total nodules = 2041 responses) is used to characterize human detection performance. Metrics of complexity based on the local density and orientation of distracting vasculature are developed for two-dimensional (2-D) and three-dimensional (3-D) considerations of the image volume. Assessed characteristics included the distribution of 2-D/3-D vessel structures of differing orientation (dubbed "2-D/3-D and dot-like/line-like distractor indices"), contiguity of inserted nodules with local vasculature, mean local gray-level surrounding each nodule, the proportion of lung voxels to total voxels in each section, and 3-D distance of each nodule from the trachea bifurcation. A generalized linear mixed-effects statistical model is used to determine the influence of each these metrics on nodule detectability. In order of decreasing effect size: 3-D line-like distractor index, 2-D line-like distractor index, 2-D dot-like distractor index, local mean gray-level, contiguity with 2-D dots, lung area, and contiguity with 3-D lines all significantly affect detectability ( ). These data demonstrate that local lung complexity degrades detection of lung nodules.
• Wood, A. M., Grotegut, C. A., Ronald, J., Pabon-Ramos, W., Pedro, C., Knechtle, S. J., Wysokinska, E., Rubin, G. D., Brady, C. W., & Gilner, J. B. (2018). Identification and Management of Abdominal Wall Varices in Pregnancy. Obstetrics and gynecology, 132(4), 882-887.
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  Portal hypertension in pregnancy is associated with elevated risk of variceal hemorrhage. Ectopic varices, those located outside the esophagus or stomach, are rare but have a high risk of associated maternal morbidity or mortality.
• Bankier, A. A., MacMahon, H., Goo, J. M., Rubin, G. D., Schaefer-Prokop, C. M., & Naidich, D. P. (2017). Recommendations for Measuring Pulmonary Nodules at CT: A Statement from the Fleischner Society. Radiology, 285(2), 584-600.
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  These recommendations for measuring pulmonary nodules at computed tomography (CT) are a statement from the Fleischner Society and, as such, incorporate the opinions of a multidisciplinary international group of thoracic radiologists, pulmonologists, surgeons, pathologists, and other specialists. The recommendations address nodule size measurements at CT, which is a topic of importance, given that all available guidelines for nodule management are essentially based on nodule size or changes thereof. The recommendations are organized according to practical questions that commonly arise when nodules are measured in routine clinical practice and are, together with their answers, summarized in a table. The recommendations include technical requirements for accurate nodule measurement, directions on how to accurately measure the size of nodules at the workstation, and directions on how to report nodule size and changes in size. The recommendations are designed to provide practical advice based on the available evidence from the literature; however, areas of uncertainty are also discussed, and topics needing future research are highlighted. RSNA, 2017 Online supplemental material is available for this article.
• Boll, D. T., Rubin, G. D., Heye, T., & Pierce, L. J. (2017). Affinity Chart Analysis: A Method for Structured Collection, Aggregation, and Response to Customer Needs in Radiology. AJR. American journal of roentgenology, 208(4), W134-W145.
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  The objective of this study is to analyze implementation of the voice-of-the-customer method to assess the current state of image postprocessing and reporting delivered by a radiology department and to plan improvements on the basis of referring physicians' preferences.
• Ebner, L., Tall, M., Choudhury, K. R., Ly, D. L., Roos, J. E., Napel, S., & Rubin, G. D. (2017). Variations in the functional visual field for detection of lung nodules on chest computed tomography: Impact of nodule size, distance, and local lung complexity. Medical physics, 44(7), 3483-3490.
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  To explore the characteristics that impact lung nodule detection by peripheral vision when searching for lung nodules on chest CT-scans.
• MacMahon, H., Naidich, D. P., Goo, J. M., Lee, K. S., Leung, A. N., Mayo, J. R., Mehta, A. C., Ohno, Y., Powell, C. A., Prokop, M., Rubin, G. D., Schaefer-Prokop, C. M., Travis, W. D., Van Schil, P. E., & Bankier, A. A. (2017). Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017. Radiology, 284(1), 228-243.
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  The Fleischner Society Guidelines for management of solid nodules were published in 2005, and separate guidelines for subsolid nodules were issued in 2013. Since then, new information has become available; therefore, the guidelines have been revised to reflect current thinking on nodule management. The revised guidelines incorporate several substantive changes that reflect current thinking on the management of small nodules. The minimum threshold size for routine follow-up has been increased, and recommended follow-up intervals are now given as a range rather than as a precise time period to give radiologists, clinicians, and patients greater discretion to accommodate individual risk factors and preferences. The guidelines for solid and subsolid nodules have been combined in one simplified table, and specific recommendations have been included for multiple nodules. These guidelines represent the consensus of the Fleischner Society, and as such, they incorporate the opinions of a multidisciplinary international group of thoracic radiologists, pulmonologists, surgeons, pathologists, and other specialists. Changes from the previous guidelines issued by the Fleischner Society are based on new data and accumulated experience. RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on March 13, 2017.
• Rubin, G. D. (2017). Costing in Radiology and Health Care: Rationale, Relativity, Rudiments, and Realities. Radiology, 282(2), 333-347.
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  Costs direct decisions that influence the effectiveness of radiology in the care of patients on a daily basis. Yet many radiologists struggle to harness the power of cost measurement and cost management as a critical path toward establishing their value in patient care. When radiologists cannot articulate their value, they risk losing control over how imaging is delivered and supported. In the United States, recent payment trends directing value-based payments for bundles of care advance the imperative for radiology providers to articulate their value. This begins with the development of an understanding of the providers' own costs, as well as the complex interrelationships and imaging-associated costs of other participants across the imaging value chain. Controlling the costs of imaging necessitates understanding them at a procedural level and quantifying the costs of delivering specific imaging services. Effective product-level costing is dependent on a bottom-up approach, which is supported through recent innovations in time-dependent activity-based costing. Once the costs are understood, they can be managed. Within the high fixed cost and high overhead cost environment of health care provider organizations, stakeholders must understand the implications of misaligned top-down cost management approaches that can both paradoxically shift effort from low-cost workers to much costlier professionals and allocate overhead costs counterproductively. Radiology's engagement across a broad spectrum of care provides an excellent opportunity for radiology providers to take a leading role within the health care organizations to enhance value and margin through principled and effective cost management. Following a discussion of the rationale for measuring costs, this review contextualizes costs from the perspectives of a variety of stakeholders (relativity), discusses core concepts in how costs are classified (rudiments), presents common and improved methods for measuring costs in health care, and discusses how cost management strategies can either improve or hinder high-value health care (realities). RSNA, 2017 Online supplemental material is available for this article.
• Rubin, G. D., & Krupinski, E. A. (2017). Tracking Eye Movements during CT Interpretation: Inferences of Reader Performance and Clinical Competency Require Clinically Realistic Procedures for Unconstrained Search. Radiology, 283(3), 920.
• Rubin, G. D., & Patel, B. N. (2017). Financial Forecasting and Stochastic Modeling: Predicting the Impact of Business Decisions. Radiology, 283(2), 342-358.
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  In health care organizations, effective investment of precious resources is critical to assure that the organization delivers high-quality and sustainable patient care within a supportive environment for patients, their families, and the health care providers. This holds true for organizations independent of size, from small practices to large health systems. For radiologists whose role is to oversee the delivery of imaging services and the interpretation, communication, and curation of imaging-informed information, business decisions influence where and how they practice, the tools available for image acquisition and interpretation, and ultimately their professional satisfaction. With so much at stake, physicians must understand and embrace the methods necessary to develop and interpret robust financial analyses so they effectively participate in and better understand decision making. This review discusses the financial drivers upon which health care organizations base investment decisions and the central role that stochastic financial modeling should play in support of strategically aligned capital investments. Given a health care industry that has been slow to embrace advanced financial analytics, a fundamental message of this review is that the skills and analytical tools are readily attainable and well worth the effort to implement in the interest of informed decision making. RSNA, 2017 Online supplemental material is available for this article.
• Rubin, G. D., Krishnaraj, A., Mahesh, M., Rajendran, R. R., & Fishman, E. K. (2017). Enhancing Public Access to Relevant and Valued Medical Information: Fresh Directions for RadiologyInfo.org. Journal of the American College of Radiology : JACR, 14(5), 697-702.e4.
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  RadiologyInfo.org is a public information portal designed to support patient care and broaden public awareness of the essential role radiology plays in overall patient health care. Over the past 14 years, RadiologyInfo.org has evolved considerably to provide access to more than 220 mixed-media descriptions of tests, treatments, and diseases through a spectrum of mobile and desktop platforms, social media, and downloadable documents in both English and Spanish. In 2014, the RSNA-ACR Public Information Website Committee, which stewards RadiologyInfo.org, developed 3- to 5-year strategic and implementation plans for the website. The process was informed by RadiologyInfo.org user surveys, formal stakeholder interviews, focus groups, and usability testing. Metrics were established as key performance indicators to assess progress toward the stated goals of (1) optimizing content to enhance patient-centeredness, (2) enhancing reach and engagement, and (3) maintaining sustainability. Major changes resulting from this process include a complete redesign of the website, the replacement of text-rich PowerPoint presentations with conversational videos, and the development of an affiliate network. Over the past year, visits to RadiologyInfo.org have increased by 60.27% to 1,424,523 in August 2016 from 235 countries and territories. Twenty-two organizations have affiliated with RadiologyInfo.org with new organizations being added on a monthly basis. RadiologyInfo provides a tangible demonstration of how radiologists can engage directly with the global public to educate them on the value of radiology in their health care and to allay concerns and dispel misconceptions. Regular self-assessment and responsive planning will ensure its continued growth and relevance.
• Rubin, G. D., McNeil, B. J., Palkó, A., Thrall, J. H., Krestin, G. P., Muellner, A., & Kressel, H. Y. (2017). External Factors That Influence the Practice of Radiology: Proceedings of the International Society for Strategic Studies in Radiology Meeting. Radiology, 283(3), 845-853.
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  In both the United States and Europe, efforts to reduce soaring health care costs have led to intense scrutiny of both standard and innovative uses of imaging. Given that the United States spends a larger share of its gross domestic product on health care than any other nation and also has the most varied health care financing and delivery systems in the world, it has become an especially fertile environment for developing and testing approaches to controlling health care costs and value. This report focuses on recent reforms that have had a dampening effect on imaging use in the United States and provides a glimpse of obstacles that imaging practices may soon face or are already facing in other countries. On the basis of material presented at the 2015 meeting of the International Society for Strategic Studies in Radiology, this report outlines the effects of reforms aimed at (a) controlling imaging use, (b) controlling payer expense through changes in benefit design, and (c) controlling both costs and quality through "value-based" payment schemes. Reasons are considered for radiology practices on both sides of the Atlantic about why the emphasis needs to shift from providing a large volume of imaging services to increasing the value of imaging as manifested in clinical outcomes, patient satisfaction, and overall system savings. Options for facilitating the shift from volume to value are discussed, from the use of advanced management strategies that improve workflow to the creation of programs for patient engagement, the development of new clinical decision-making support tools, and the validation of clinically relevant imaging biomarkers. Radiologists in collaboration with industry must enhance their efforts to expand the performance of comparative effectiveness research to establish the value of these initiatives, while being mindful of the importance of minimizing conflicts of interest. RSNA, 2017.
• Cury, R. C., Abbara, S., Achenbach, S., Agatston, A., Berman, D. S., Budoff, M. J., Dill, K. E., Jacobs, J. E., Maroules, C. D., Rubin, G. D., Rybicki, F. J., Schoepf, U. J., Shaw, L. J., Stillman, A. E., White, C. S., Woodard, P. K., & Leipsic, J. A. (2016). CAD-RADS™: Coronary Artery Disease - Reporting and Data System: An Expert Consensus Document of the Society of Cardiovascular Computed Tomography (SCCT), the American College of Radiology (ACR) and the North American Society for Cardiovascular Imaging (NASCI). Endorsed by the American College of Cardiology. Journal of the American College of Radiology : JACR, 13(12 Pt A), 1458-1466.e9.
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  The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care.
• Cury, R. C., Abbara, S., Achenbach, S., Agatston, A., Berman, D. S., Budoff, M. J., Dill, K. E., Jacobs, J. E., Maroules, C. D., Rubin, G. D., Rybicki, F. J., Schoepf, U. J., Shaw, L. J., Stillman, A. E., White, C. S., Woodard, P. K., & Leipsic, J. A. (2016). Coronary Artery Disease - Reporting and Data System (CAD-RADS): An Expert Consensus Document of SCCT, ACR and NASCI: Endorsed by the ACC. JACC. Cardiovascular imaging, 9(9), 1099-1113.
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  The intent of CAD-RADS - Coronary Artery Disease Reporting and Data System is to create a standardized method to communicate findings of coronary CT angiography (coronary CTA) in order to facilitate decision-making regarding further patient management. The suggested CAD-RADS classification is applied on a per-patient basis and represents the highest-grade coronary artery lesion documented by coronary CTA. It ranges from CAD-RADS 0 (Zero) for the complete absence of stenosis and plaque to CAD-RADS 5 for the presence of at least one totally occluded coronary artery and should always be interpreted in conjunction with the impression found in the report. Specific recommendations are provided for further management of patients with stable or acute chest pain based on the CAD-RADS classification. The main goal of CAD-RADS is to standardize reporting of coronary CTA results and to facilitate communication of test results to referring physicians along with suggestions for subsequent patient management. In addition, CAD-RADS will provide a framework of standardization that may benefit education, research, peer-review and quality assurance with the potential to ultimately result in improved quality of care.
• Mark, D., Federspiel, J., Cowper, P., Anstrom, K., Hoffmann, U., Patel, M., Davidson-Ray, L., Daniels, M., Cooper, L., Knight, J., Lee, K., Douglas, P., Bonow, R., Anderson, G., Bertoni, A., Carr, J., Min, J., Proschan, M., Spertus, J., , Ulrich, C., et al. (2016). Economic outcomes with anatomical versus functional diagnostic testing for coronary artery disease. Annals of Internal Medicine, 165(2). doi:10.7326/M15-2639
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  Background: PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain) found that initial use of at least 64-slice multidetector computed tomography angiography (CTA) versus functional diagnostic testing strategies did not improve clinical outcomes in stable symptomatic patients with suspected coronary artery disease (CAD) requiring noninvasive testing. Objective: To conduct an economic analysis for PROMISE (a major secondary aim of the study). Design: Prospective economic study from the U.S. perspective. Comparisons were made according to the intention-to-treat principle, and CIs were calculated using bootstrap methods. (ClinicalTrials.gov: NCT01174550) Setting: 190 U.S. centers. Patients: 9649 U.S. patients enrolled in PROMISE between July 2010 and September 2013. Median follow-up was 25 months. Measurements: Technical costs of the initial (outpatient) testing strategy were estimated from Premier Research Database data. Hospital-based costs were estimated using hospital bills and Medicare cost-charge ratios. Physician fees were taken from the Medicare Physician Fee Schedule. Costs were expressed in 2014 U.S. dollars, discounted at 3% annually, and estimated out to 3 years using inverse probability weighting methods. Results: The mean initial testing costs were $174 for exercise electrocardiography; $404 for CTA; $501 to $514 for pharmacologic and exercise stress echocardiography, respectively; and $946 to $1132 for exercise and pharmacologic stress nuclear testing, respectively. Mean costs at 90 days were $2494 for the CTA strategy versus $2240 for the functional strategy (mean difference, $254 [95% CI, $634 to $906]). The difference was associated with more revascularizations and catheterizations (4.25 per 100 patients) with CTA use. After 90 days, the mean cost difference between the groups out to 3 years remained small. Limitation: Cost weights for test strategies were obtained from sources outside PROMISE. Conclusion: Computed tomography angiography and functional diagnostic testing strategies in patients with suspected CAD have similar costs through 3 years of follow-up.
• Meinel, F. G., Haack, M., Weidenhagen, R., Hellbach, K., Rottenkolber, M., Armbruster, M., Jerkku, T., Thierfelder, K. M., Plum, J. L., Koeppel, T. A., Rubin, G. D., & Sommer, W. H. (2016). Effect of endoleaks on changes in aortoiliac volume after endovascular repair for abdominal aortic aneurysm. Clinical hemorheology and microcirculation, 64(2), 135-147.
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  To evaluate changes in aortoiliac volume after endovascular repair (EVAR) for abdominal aortic aneurysm (AAA) in patients with and without endoleaks.
• Patel, B. N., & Rubin, G. D. (2016). Deal or No Deal? Negotiation 101. Journal of the American College of Radiology : JACR, 13(6), 756-8.
• Rubin, G. D. (2016). An Organizational Perspective and a Team Approach: Keys to Successful Business Planning. Journal of the American College of Radiology : JACR, 13(2), 228-9.
• Boiselle, P. M., Bardo, D. M., Rubin, G. D., & Tack, D. (2015). Expert Opinion: Is there Still a Role for Filtered-back Projection Reconstruction in Cardiothoracic CT?. Journal of thoracic imaging, 30(4), 219.
• Rubin, G. D. (2015). Lung nodule and cancer detection in computed tomography screening. Journal of thoracic imaging, 30(2), 130-8.
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  Fundamental to the diagnosis of lung cancer in computed tomography (CT) scans is the detection and interpretation of lung nodules. As the capabilities of CT scanners have advanced, higher levels of spatial resolution reveal tinier lung abnormalities. Not all detected lung nodules should be reported; however, radiologists strive to detect all nodules that might have relevance to cancer diagnosis. Although medium to large lung nodules are detected consistently, interreader agreement and reader sensitivity for lung nodule detection diminish substantially as the nodule size falls below 8 to 10 mm. The difficulty in establishing an absolute reference standard presents a challenge to the reliability of studies performed to evaluate lung nodule detection. In the interest of improving detection performance, investigators are using eye tracking to analyze the effectiveness with which radiologists search CT scans relative to their ability to recognize nodules within their search path in order to determine whether strategies might exist to improve performance across readers. Beyond the viewing of transverse CT reconstructions, image processing techniques such as thin-slab maximum-intensity projections are used to substantially improve reader performance. Finally, the development of computer-aided detection has continued to evolve with the expectation that one day it will serve routinely as a tireless partner to the radiologist to enhance detection performance without significant prolongation of the interpretive process. This review provides an introduction to the current understanding of these varied issues as we enter the era of widespread lung cancer screening.
• Rubin, G. D., Roos, J. E., Tall, M., Harrawood, B., Bag, S., Ly, D. L., Seaman, D. M., Hurwitz, L. M., Napel, S., & Roy Choudhury, K. (2015). Characterizing search, recognition, and decision in the detection of lung nodules on CT scans: elucidation with eye tracking. Radiology, 274(1), 276-86.
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  To determine the effectiveness of radiologists' search, recognition, and acceptance of lung nodules on computed tomographic (CT) images by using eye tracking.
• Mark, D. B., Anderson, J. L., Brinker, J. A., Brophy, J. A., Casey, D. E., Cross, R. R., Edmundowicz, D., Hachamovitch, R., Hlatky, M. A., Jacobs, J. E., Jaskie, S., Kett, K. G., Malhotra, V., Masoudi, F. A., McConnell, M. V., Rubin, G. D., Shaw, L. J., Sherman, M. E., Stanko, S., & Ward, R. P. (2014). ACC/AHA/ASE/ASNC/HRS/IAC/Mended Hearts/NASCI/RSNA/SAIP/SCAI/SCCT/SCMR/SNMMI 2014 health policy statement on use of noninvasive cardiovascular imaging: a report of the American College of Cardiology Clinical Quality Committee. Journal of the American College of Cardiology, 63(7), 698-721.
• Rubin, G. D. (2014). Computed tomography: revolutionizing the practice of medicine for 40 years. Radiology, 273(2 Suppl), S45-74.
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  Computed tomography (CT) has had a profound effect on the practice of medicine. Both the spectrum of clinical applications and the role that CT has played in enhancing the depth of our understanding of disease have been profound. Although almost 90 000 articles on CT have been published in peer-reviewed journals over the past 40 years, fewer than 5% of these have been published in Radiology. Nevertheless, these almost 4000 articles have provided a basis for many important medical advances. By enabling a deepened understanding of anatomy, physiology, and pathology, CT has facilitated key advances in the detection and management of disease. This article celebrates this breadth of scientific discovery and development by examining the impact that CT has had on the diagnosis, characterization, and management of a sampling of major health challenges, including stroke, vascular diseases, cancer, trauma, acute abdominal pain, and diffuse lung diseases, as related to key technical advances in CT and manifested in Radiology.
• Rubin, G. D., Leipsic, J., Joseph Schoepf, U., Fleischmann, D., & Napel, S. (2014). CT angiography after 20 years: a transformation in cardiovascular disease characterization continues to advance. Radiology, 271(3), 633-52.
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  Through a marriage of spiral computed tomography (CT) and graphical volumetric image processing, CT angiography was born 20 years ago. Fueled by a series of technical innovations in CT and image processing, over the next 5-15 years, CT angiography toppled conventional angiography, the undisputed diagnostic reference standard for vascular disease for the prior 70 years, as the preferred modality for the diagnosis and characterization of most cardiovascular abnormalities. This review recounts the evolution of CT angiography from its development and early challenges to a maturing modality that has provided unique insights into cardiovascular disease characterization and management. Selected clinical challenges, which include acute aortic syndromes, peripheral vascular disease, aortic stent-graft and transcatheter aortic valve assessment, and coronary artery disease, are presented as contrasting examples of how CT angiography is changing our approach to cardiovascular disease diagnosis and management. Finally, the recently introduced capabilities for multispectral imaging, tissue perfusion imaging, and radiation dose reduction through iterative reconstruction are explored with consideration toward the continued refinement and advancement of CT angiography.
• Toth, D. F., Töpker, M., Mayerhöfer, M. E., Rubin, G. D., Furtner, J., Asenbaum, U., Karanikas, G., Weber, M., Czerny, C., Herold, C. J., & Ringl, H. (2014). Rapid detection of bone metastasis at thoracoabdominal CT: accuracy and efficiency of a new visualization algorithm. Radiology, 270(3), 825-33.
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  To retrospectively assess the use of a combination of cancellous bone reconstructions (CBR) and multiplanar reconstructions (MPRs) for the detection of bone metastases at thoracoabdominal computed tomography (CT) compared with the use of MPRs alone.
• Ueda, T., Takaoka, H., Petrovitch, I., & Rubin, G. D. (2014). Detection of broken sutures and metal-ring fractures in AneuRx stent-grafts by using three-dimensional CT angiography after endovascular abdominal aortic aneurysm repair: association with late endoleak development and device migration. Radiology, 272(1), 275-83.
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  To determine the prevalence of demonstrable stent-graft degradation by using three-dimensional computed tomographic (CT) angiography to assess endoleak and stent-graft migration after endovascular aortic aneurysm repair (EVAR).
• Christe, A., Lin, M., Yen, A., Hallett, R., Roychoudhury, K., Schmitzberger, F., Fleischmann, D., Leung, A., Rubin, G., Vock, P., & Roos, J. (2013). Erratum: CT patterns of fungal pulmonary infections of the lung: Comparison of standard-dose and simulated low-dose CT (European Journal of Radiology (2012) 81 (2860-2866)). European Journal of Radiology, 82(11). doi:10.1016/j.ejrad.2013.07.021
• Lee, G. K., Fox, P. M., Riboh, J., Hsu, C., Saber, S., Rubin, G. D., & Chang, J. (2013). Computed tomography angiography in microsurgery: indications, clinical utility, and pitfalls. Eplasty, 13, e42.
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  Computed tomographic angiography (CTA) can be used to obtain 3-dimensional vascular images and soft-tissue definition. The goal of this study was to evaluate the reliability, usefulness, and pitfalls of CTA in preoperative planning of microvascular reconstructive surgery.
• Rubin, G. D. (2013). Emerging and evolving roles for CT in screening for coronary heart disease. Journal of the American College of Radiology : JACR, 10(12), 943-8.
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  Coronary heart disease (CHD) is highly prevalent and is the primary cause of death for both men and women, worldwide. Because the disease develops over many years, there are opportunities to intervene and alter the course of CHD, assuming that there are reliable means for determining which individuals with coronary atherosclerosis will develop symptomatic CHD. CT provides 2 distinct means for coronary artery disease assessment--coronary artery calcium (CAC) measurement using noncontrast CT and coronary CT angiography (cCTA). The recent refinement of electrocardiographic triggering and gating with CT has enabled these techniques to be performed with greater reliability and substantially lower radiation exposure. This has led to widening availability of these diagnostic techniques and rapid expansion of our understanding of their potential clinical use. Within the context of CHD, 2 applications are particularly compelling--risk stratification of asymptomatic individuals with the intent of targeting therapy to prevent CHD and as gatekeeper to cardiac catheterization to minimize unnecessary invasive diagnostic coronary procedures. This review highlights key insights from recent investigations of CHD development and CT application toward the management of individuals at risk of developing or suspected of having CHD.
• Won, J. H., Jeon, Y., Rosenberg, J. K., Yoon, S., Rubin, G. D., & Napel, S. (2013). Uncluttered Single-Image Visualization of Vascular Structures Using GPU and Integer Programming. IEEE transactions on visualization and computer graphics, 19(1), 81-93.
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  Direct projection of 3D branching structures, such as networks of cables, blood vessels, or neurons onto a 2D image creates the illusion of intersecting structural parts and creates challenges for understanding and communication. We present a method for visualizing such structures, and demonstrate its utility in visualizing the abdominal aorta and its branches, whose tomographic images might be obtained by computed tomography or magnetic resonance angiography, in a single 2D stylistic image, without overlaps among branches. The visualization method, termed uncluttered single-image visualization (USIV), involves optimization of geometry. This paper proposes a novel optimization technique that utilizes an interesting connection of the optimization problem regarding USIV to the protein structure prediction problem. Adopting the integer linear programming-based formulation for the protein structure prediction problem, we tested the proposed technique using 30 visualizations produced from five patient scans with representative anatomical variants in the abdominal aortic vessel tree. The novel technique can exploit commodity-level parallelism, enabling use of general-purpose graphics processing unit (GPGPU) technology that yields a significant speedup. Comparison of the results with the other optimization technique previously reported elsewhere suggests that, in most aspects, the quality of the visualization is comparable to that of the previous one, with a significant gain in the computation time of the algorithm.
• Christe, A., Lin, M. C., Yen, A. C., Hallett, R. L., Roychoudhury, K., Schmitzberger, F., Fleischmann, D., Leung, A. N., Rubin, G. D., Rubin, G. D., Vock, P., & Roos, J. E. (2012). CT patterns of fungal pulmonary infections of the lung: comparison of standard-dose and simulated low-dose CT. European journal of radiology, 81(10), 2860-6.
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  To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients.
• Pierce, L., Raman, K., Rosenberg, J., & Rubin, G. D. (2012). Quality Improvement in 3D Imaging. AJR. American journal of roentgenology, 198(1), 150-5.
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  The purpose of this study was to assess the effect of a quality control program on reducing errors in the generation of 3D images.
• Sommer, W. H., Becker, C. R., Haack, M., Rubin, G. D., Weidenhagen, R., Schwarz, F., Nikolaou, K., Reiser, M. F., Johnson, T. R., & Clevert, D. A. (2012). Time-resolved CT angiography for the detection and classification of endoleaks. Radiology, 263(3), 917-26.
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  To assess the feasibility and diagnostic performance of time-resolved computed tomographic (CT) angiography in the detection and classification of endoleaks after endovascular aortic aneurysm repair (EVAR) in high-risk patients.
• Takaoka, H., Ishibashi, I., Uehara, M., Rubin, G. D., Komuro, I., & Funabashi, N. (2012). Comparison of image characteristics of plaques in culprit coronary arteries by 64 slice CT and intravascular ultrasound in acute coronary syndromes. International journal of cardiology, 160(2), 119-26.
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  To evaluate plaque image characteristics in coronary artery culprit-lesions in subjects with acute coronary syndromes (ACS), we retrospectively compared coronary arterial images by 64-slice CT before conventional-coronary-angiogram with those by intravascular ultrasound (IVUS).
• Tall, M., Choudhury, K. R., Napel, S., Roos, J. E., & Rubin, G. D. (2012). Accuracy of a remote eye tracker for radiologic observer studies: effects of calibration and recording environment. Academic radiology, 19(2), 196-202.
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  To determine the accuracy and reproducibility of a remote eye-tracking system for studies of observer gaze while displaying volumetric chest computed tomography (CT) images.
• Marin, D., Nelson, R. C., Rubin, G. D., & Schindera, S. T. (2011). Body CT: technical advances for improving safety. AJR. American journal of roentgenology, 197(1), 33-41.
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  In this review, we attempt to address many of the issues that are related to ensuring patient benefit in body CT, balancing the use of ionizing radiation and iodinated contrast media. We attempt to not only summarize the literature but also make recommendations relevant to CT protocols, including the technical parameters of both the scanner and the associated contrast media.
• Nakatamari, H., Ueda, T., Ishioka, F., Raman, B., Kurihara, K., Rubin, G. D., Ito, H., & Sze, D. Y. (2011). Discriminant analysis of native thoracic aortic curvature: risk prediction for endoleak formation after thoracic endovascular aortic repair. Journal of vascular and interventional radiology : JVIR, 22(7), 974-979.e2.
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  To determine the association of native thoracic aortic curvature measured from computed tomographic (CT) angiography categorized by discriminant analysis with the development of endoleaks after thoracic endovascular aortic repair (EVAR).
• Pu, J., Paik, D. S., Meng, X., Roos, J. E., & Rubin, G. D. (2011). Shape "break-and-repair" strategy and its application to automated medical image segmentation. IEEE transactions on visualization and computer graphics, 17(1), 115-24.
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  In three-dimensional medical imaging, segmentation of specific anatomy structure is often a preprocessing step for computer-aided detection/diagnosis (CAD) purposes, and its performance has a significant impact on diagnosis of diseases as well as objective quantitative assessment of therapeutic efficacy. However, the existence of various diseases, image noise or artifacts, and individual anatomical variety generally impose a challenge for accurate segmentation of specific structures. To address these problems, a shape analysis strategy termed "break-and-repair" is presented in this study to facilitate automated medical image segmentation. Similar to surface approximation using a limited number of control points, the basic idea is to remove problematic regions and then estimate a smooth and complete surface shape by representing the remaining regions with high fidelity as an implicit function. The innovation of this shape analysis strategy is the capability of solving challenging medical image segmentation problems in a unified framework, regardless of the variability of anatomical structures in question. In our implementation, principal curvature analysis is used to identify and remove the problematic regions and radial basis function (RBF) based implicit surface fitting is used to achieve a closed (or complete) surface boundary. The feasibility and performance of this strategy are demonstrated by applying it to automated segmentation of two completely different anatomical structures depicted on CT examinations, namely human lungs and pulmonary nodules. Our quantitative experiments on a large number of clinical CT examinations collected from different sources demonstrate the accuracy, robustness, and generality of the shape "break-and-repair" strategy in medical image segmentation.
• Raman, B., Raman, R., Rubin, G. D., & Napel, S. (2011). Automated tracing of the adventitial contour of aortoiliac and peripheral arterial walls in CT angiography (CTA) to allow calculation of non-calcified plaque burden. Journal of digital imaging, 24(6), 1078-86.
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  Aortoiliac and lower extremity arterial atherosclerotic plaque burden is a risk factor for the development of visceral and peripheral ischemic and aneurismal vascular disease. While prior research allows automated quantification of calcified plaque in these body regions using CT angiograms, no automated method exists to quantify soft plaque. We developed an automatic algorithm that defines the outer wall contour and wall thickness of vessels to quantify non-calcified plaque in CT angiograms of the chest, abdomen, pelvis, and lower extremities. The algorithm encodes the search space as a constrained graph and calculates the outer wall contour by deriving a minimum cost path through the graph, following the visible outer wall contour while minimizing path tortuosity. Our algorithm was statistically equivalent to a reference standard made by two reviewers. Absolute error was 1.9 ± 2.3% compared to the inter-observer variability of 3.9 ± 3.6%. Wall thickness in vessels with atherosclerosis was 3.4 ± 1.6 mm compared to 1.2 ± 0.4 mm in normal vessels. The algorithm shows promise as a tool for quantification of non-calcified plaque in CT angiography. When combined with previous research, our method has the potential to quantify both non-calcified and calcified plaque in all clinically significant systemic arteries, from the thoracic aorta to the arteries of the calf, over a wide range of diameters. This algorithm has the potential to enable risk stratification of patients and facilitate investigations into the relationships between asymptomatic atherosclerosis and a variety of behavioral, physiologic, pathologic, and genotypic conditions.
• Ueda, T., Takaoka, H., Raman, B., Rosenberg, J., & Rubin, G. D. (2011). Impact of quantitatively determined native thoracic aortic tortuosity on endoleak development after thoracic endovascular aortic repair. AJR. American journal of roentgenology, 197(6), W1140-6.
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  The objective of our study was to assess whether there is an association between native thoracic aortic curvature and the development of endoleaks after thoracic endovascular aortic repair.
• , A. C., Mark, D. B., Berman, D. S., Budoff, M. J., Carr, J. J., Gerber, T. C., Hecht, H. S., Hlatky, M. A., Hodgson, J. M., Lauer, M. S., Miller, J. M., Morin, R. L., Mukherjee, D., Poon, M., Rubin, G. D., & Schwartz, R. S. (2010). ACCF/ACR/AHA/NASCI/SAIP/SCAI/SCCT 2010 expert consensus document on coronary computed tomographic angiography: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. Circulation, 121(22), 2509-43.
• , A. C., Mark, D. B., Berman, D. S., Budoff, M. J., Carr, J. J., Gerber, T. C., Hecht, H. S., Hlatky, M. A., Hodgson, J. M., Lauer, M. S., Miller, J. M., Morin, R. L., Mukherjee, D., Poon, M., Rubin, G. D., & Schwartz, R. S. (2010). ACCF/ACR/AHA/NASCI/SAIP/SCAI/SCCT 2010 expert consensus document on coronary computed tomographic angiography: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. Journal of the American College of Cardiology, 55(23), 2663-99.
• Choudhury, K. R., Paik, D. S., Yi, C. A., Napel, S., Roos, J., & Rubin, G. D. (2010). Assessing operating characteristics of CAD algorithms in the absence of a gold standard. Medical physics, 37(4), 1788-95.
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  The authors examine potential bias when using a reference reader panel as "gold standard" for estimating operating characteristics of CAD algorithms for detecting lesions. As an alternative, the authors propose latent class analysis (LCA), which does not require an external gold standard to evaluate diagnostic accuracy.
• Hellinger, J. C., Epelman, M., & Rubin, G. D. (2010). Upper extremity computed tomographic angiography: state of the art technique and applications in 2010. Radiologic clinics of North America, 48(2), 397-421, ix.
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  From technical and interpretative perspectives, upper extremity computed tomographic angiography (CTA) is one of the more challenging vascular CTA applications. Synchronizing the relatively large scan coverage with a single bolus of contrast medium requires precise selection of acquisition and contrast delivery parameters. To avoid multiple acquisitions and minimize radiation exposure and contrast medium volume, it is important to have fundamental knowledge on how to select these parameters. Equally important is knowing how to adeptly apply advanced workstation visualization techniques and tool functions for the upper extremity vascular tree. In this review, upper extremity arterial and venous anatomy is discussed, followed by a detailed overview on state-of-the-art upper extremity CTA technical considerations and strategies. The review concludes with discussion and illustration of upper extremity CTA clinical applications.
• Lee, C. I., Tsai, E. B., Sigal, B. M., Plevritis, S. K., Garber, A. M., & Rubin, G. D. (2010). Incidental extracardiac findings at coronary CT: clinical and economic impact. AJR. American journal of roentgenology, 194(6), 1531-8.
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  The purpose of this study was to evaluate the prevalence of incidental extracardiac findings on coronary CT, to determine the associated downstream resource utilization, and to estimate additional costs per patient related to the associated diagnostic workup.
• Mark, D. B., Berman, D. S., Budoff, M. J., Carr, J. J., Gerber, T. C., Hecht, H. S., Hlatky, M. A., Hodgson, J. M., Lauer, M. S., Miller, J. M., Morin, R. L., Mukherjee, D., Poon, M., Rubin, G. D., Schwartz, R. S., & , A. C. (2010). ACCF/ACR/AHA/NASCI/SAIP/SCAI/SCCT 2010 expert consensus document on coronary computed tomographic angiography: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions, 76(2), E1-42.
• Raman, B., Raman, R., Napel, S., & Rubin, G. D. (2010). Automated quantification of aortoaortic and aortoiliac angulation for computed tomographic angiography of abdominal aortic aneurysms before endovascular repair: preliminary study. Journal of vascular and interventional radiology : JVIR, 21(11), 1746-50.
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  The degree of angulation of abdominal aortic aneurysms (AAAs) has emerged as an important factor in assessing eligibility for endovascular aneurysm repair (EVAR). The authors developed an automatic algorithm that reduces variability of measurement of aortoiliac angulation. For highly structured manual methods, intraobserver variability was 8.2 degrees ± 5.0 (31% ± 20) and interobserver variability was 5.6 degrees ± 2.5 (20% ± 9.1) compared with 0.6 degrees ± 0.8 (2.2% ± 3.6) (intraobserver) and 0.4 degrees ± 0.4 (1.4% ± 1.9) (interobserver) for the automatic algorithm (P < .01). In phantoms, the automatically measured angles were equivalent to reference values (P < .05). This algorithm was also faster than manual methods and has the potential to enhance the clinical utility and reliability of computed tomographic angiography for preoperative assessment for EVAR.
• Roos, J. E., Paik, D., Olsen, D., Liu, E. G., Chow, L. C., Leung, A. N., Mindelzun, R., Choudhury, K. R., Naidich, D. P., Napel, S., & Rubin, G. D. (2010). Computer-aided detection (CAD) of lung nodules in CT scans: radiologist performance and reading time with incremental CAD assistance. European radiology, 20(3), 549-57.
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  The diagnostic performance of radiologists using incremental CAD assistance for lung nodule detection on CT and their temporal variation in performance during CAD evaluation was assessed.
• Taylor, A. J., Cerqueira, M., Hodgson, J. M., Mark, D., Min, J., O'Gara, P., Rubin, G. D., , A. C., , S. o., , A. C., , A. H., , A. S., , A. S., , N. A., , S. f., & , S. f. (2010). ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Circulation, 122(21), e525-55.
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  The American College of Cardiology Foundation, along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria. The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research.
• Taylor, A. J., Cerqueira, M., Hodgson, J. M., Mark, D., Min, J., O'Gara, P., Rubin, G. D., , A. C., , S. o., , A. C., , A. H., , A. S., , A. S., , N. A., , S. f., , S. f., Kramer, C. M., Berman, D., Brown, A., , Chaudhry, F. A., et al. (2010). ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. Journal of the American College of Cardiology, 56(22), 1864-94.
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  The American College of Cardiology Foundation (ACCF), along with key specialty and subspecialty societies, conducted an appropriate use review of common clinical scenarios where cardiac computed tomography (CCT) is frequently considered. The present document is an update to the original CCT/cardiac magnetic resonance (CMR) appropriateness criteria published in 2006, written to reflect changes in test utilization, to incorporate new clinical data, and to clarify CCT use where omissions or lack of clarity existed in the original criteria (1). The indications for this review were drawn from common applications or anticipated uses, as well as from current clinical practice guidelines. Ninety-three clinical scenarios were developed by a writing group and scored by a separate technical panel on a scale of 1 to 9 to designate appropriate use, inappropriate use, or uncertain use. In general, use of CCT angiography for diagnosis and risk assessment in patients with low or intermediate risk or pretest probability for coronary artery disease (CAD) was viewed favorably, whereas testing in high-risk patients, routine repeat testing, and general screening in certain clinical scenarios were viewed less favorably. Use of noncontrast computed tomography (CT) for calcium scoring was rated as appropriate within intermediate- and selected low-risk patients. Appropriate applications of CCT are also within the category of cardiac structural and functional evaluation. It is anticipated that these results will have an impact on physician decision making, performance, and reimbursement policy, and that they will help guide future research.
• Terashima, M., Nguyen, P. K., Rubin, G. D., Meyer, C. H., Shimakawa, A., Nishimura, D. G., Ehara, S., Iribarren, C., Courtney, B. K., Go, A. S., Hlatky, M. A., Fortmann, S. P., & McConnell, M. V. (2010). Right coronary wall CMR in the older asymptomatic advance cohort: positive remodeling and associations with type 2 diabetes and coronary calcium. Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance, 12, 75.
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  Coronary wall cardiovascular magnetic resonance (CMR) is a promising noninvasive approach to assess subclinical atherosclerosis, but data are limited in subjects over 60 years old, who are at increased risk. The purpose of the study was to evaluate coronary wall CMR in an asymptomatic older cohort.
• Ueda, T., Fleischmann, D., Dake, M. D., Rubin, G. D., & Sze, D. Y. (2010). Incomplete endograft apposition to the aortic arch: bird-beak configuration increases risk of endoleak formation after thoracic endovascular aortic repair. Radiology, 255(2), 645-52.
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  To determine the clinical importance of the bird-beak configuration after thoracic endovascular aortic repair (TEVAR).
• Alexander, S. A., & Rubin, G. D. (2009). Imaging the thoracic aorta: anatomy, technical considerations, and trauma. Seminars in roentgenology, 44(1), 8-15.
• Chang, J., & Rubin, G. D. (2009). Solitary intercostal arterial trunk: a previously unreported anatomical variant. Circulation. Cardiovascular imaging, 2(6), e49-50.
• Kapoor, J., Katikireddy, C., Rubin, G., Schnittger, I., & McConnell, M. (2009). An unusual case of partial anomalous pulmonary venous drainage: Utility of the cardiac MRI. International Journal of Cardiology, 133(1). doi:10.1016/j.ijcard.2007.08.113
• Lee, K. K., Fortmann, S. P., Fair, J. M., Iribarren, C., Rubin, G. D., Varady, A., Go, A. S., Quertermous, T., & Hlatky, M. A. (2009). Insulin resistance independently predicts the progression of coronary artery calcification. American heart journal, 157(5), 939-45.
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  Change in coronary artery calcification is a surrogate marker of subclinical coronary artery disease (CAD). In the only large prospective study, CAD risk factors predicted progression of coronary artery calcium (CAC).
• Won, J. H., Rosenberg, J., Rubin, G. D., & Napel, S. (2009). Uncluttered single-image visualization of the abdominal aortic vessel tree: method and evaluation. Medical physics, 36(11), 5245-60.
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  The authors develop a method to visualize the abdominal aorta and its branches, obtained by CT or MR angiography, in a single 2D stylistic image without overlap among branches.
• Zhao, S. H., Logan, L., Schraedley, P., & Rubin, G. D. (2009). Assessment of the anterior spinal artery and the artery of Adamkiewicz using multi-detector CT angiography. Chinese medical journal, 122(2), 145-9.
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  Damage to the spinal cord after the treatment of the descending thoracic and thoracoabdominal aortic aneurysms is an uncommon but devastating complication. The artery of Adamkiewicz (AKA) is the principal arterial supply of the anterior spinal artery (ASA) in the lower thoracic and lumbar level. The purpose of this study was to evaluate the visualization of the anterior spinal artery and the artery of Adamkiewicz, the affecting factors for the detection rate using multi-detector row CT (MDCT).
• Assimes, T. L., Knowles, J. W., Basu, A., Iribarren, C., Southwick, A., Tang, H., Absher, D., Li, J., Fair, J. M., Rubin, G. D., Sidney, S., Fortmann, S. P., Go, A. S., Hlatky, M. A., Myers, R. M., Risch, N., & Quertermous, T. (2008). Susceptibility locus for clinical and subclinical coronary artery disease at chromosome 9p21 in the multi-ethnic ADVANCE study. Human molecular genetics, 17(15), 2320-8.
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  A susceptibility locus for coronary artery disease (CAD) at chromosome 9p21 has recently been reported, which may influence the age of onset of CAD. We sought to replicate these findings among white subjects and to examine whether these results are consistent with other racial/ethnic groups by genotyping three single nucleotide polymorphisms (SNPs) in the risk interval in the Atherosclerotic Disease, Vascular Function, and Genetic Epidemiology (ADVANCE) study. One or more of these SNPs was associated with clinical CAD in whites, U.S. Hispanics and U.S. East Asians. None of the SNPs were associated with CAD in African Americans although the power to detect an odds ratio (OR) in this group equivalent to that seen in whites was only 24-30%. ORs were higher in Hispanics and East Asians and lower in African Americans, but in all groups the 95% confidence intervals overlapped with ORs observed in whites. High-risk alleles were also associated with increased coronary artery calcification in controls and the magnitude of these associations by racial/ethnic group closely mirrored the magnitude observed for clinical CAD. Unexpectedly, we noted significant genotype frequency differences between male and female cases (P = 0.003-0.05). Consequently, men tended towards a recessive and women tended towards a dominant mode of inheritance. Finally, an effect of genotype on the age of onset of CAD was detected but only in men carrying two versus one or no copy of the high-risk allele and presenting with CAD at age >50 years. Further investigations in other populations are needed to confirm or refute our findings.
• Burt, J. R., Iribarren, C., Fair, J. M., Norton, L. C., Mahbouba, M., Rubin, G. D., Hlatky, M. A., Go, A. S., Fortmann, S. P., & , A. D. (2008). Incidental findings on cardiac multidetector row computed tomography among healthy older adults: prevalence and clinical correlates. Archives of internal medicine, 168(7), 756-61.
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  With the widespread use of cardiac multidetector row computed tomography (MDCT), the issue of incidental findings is receiving increasing attention. Our objectives were to evaluate the prevalence of incidental findings discovered during cardiac MDCT scanning and to identify clinical variables associated with incidental findings.
• Douglas, P. S., Cerqueria, M., Rubin, G. D., & Chin, A. S. (2008). Extracardiac findings: what is a cardiologist to do?. JACC. Cardiovascular imaging, 1(5), 682-7.
• Hsu, C. S., Hellinger, J. C., Rubin, G. D., & Chang, J. (2008). CT angiography in pediatric extremity trauma: preoperative evaluation prior to reconstructive surgery. Hand (New York, N.Y.), 3(2), 139-45.
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  Computed tomographic angiography (CTA) is a noninvasive modality for evaluating the vascular system and planning treatment strategies. The goal of this study was to validate the clinical utility of CTA in assessment of suspected pediatric extremity traumatic vascular injury, prior to emergent and delayed reconstructive surgery. A retrospective review was performed of all operative patients under 18 years of age who underwent multidetector-row CTA for evaluation of suspected extremity vascular injury. Parameters investigated included age, type of injury, referral source, temporal relationship between the injury and the CTA, CTA findings, operations performed, intraoperative findings, and clinical outcome. Between January 2002 and September 2005, 10 pediatric patients (6 males/4 females; mean age 8 years old, range 3-17) sustained either blunt (N = 8) or penetrating (N = 2) trauma and underwent CTA of the upper (N = 5) or lower extremities (N = 5). A total of 30% (3/10) of patients were referred from the emergency department acutely, 50% (5/10) were referred from the inpatient wards subacutely, and 20% (2/10) were referred from the outpatient clinics electively. Half (N = 5) underwent CTA to evaluate need for vascular repair, whereas half (N = 5) underwent CTA to evaluate local vasculature for flap reconstruction. Overall, 40% (4/10) of CTA findings were normal, whereas 60% (6/10) revealed traumatic vascular injuries. Pertinent nonvascular findings included soft tissue defects (60%, 6/10), fractures (40%, 4/10), and contracture deformities (20%, 2/10). In all cases, procedures were completed without complications, and intraoperative findings confirmed those from CTA. At a mean follow-up of 28 months, all injuries have healed without complications. CTA is a reliable noninvasive modality to evaluate pediatric patients with suspected traumatic extremity vascular injury and to plan treatment strategies for both vascular repair and extremity reconstruction.
• Iribarren, C., Hlatky, M. A., Chandra, M., Fair, J. M., Rubin, G. D., Go, A. S., Burt, J. R., & Fortmann, S. P. (2008). Incidental pulmonary nodules on cardiac computed tomography: prognosis and use. The American journal of medicine, 121(11), 989-96.
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  Small asymptomatic lung nodules are found frequently in the course of cardiac computed tomography (CT) scanning. However, the utility of assessing and reporting incidental findings in healthy, asymptomatic subjects is unknown.
• Josephs, S. C., Rowley, H. A., Rubin, G. D., & , A. H. (2008). Atherosclerotic Peripheral Vascular Disease Symposium II: vascular magnetic resonance and computed tomographic imaging. Circulation, 118(25), 2837-44.
• Kaneoya, K., Ueda, T., Suito, H., Nanazawa, Y., Tamaru, J., Isobe, K., Naya, Y., Tobe, T., Motoori, K., Yamamoto, S., Rubin, G. D., Minami, M., & Ito, H. (2008). Functional computed tomography imaging of tumor-induced angiogenesis: preliminary results of new tracer kinetic modeling using a computer discretization approach. Radiation medicine, 26(4), 213-21.
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  The aim of this study was to establish functional computed tomography (CT) imaging as a method for assessing tumor-induced angiogenesis.
• Peng, P. D., Spain, D. A., Tataria, M., Hellinger, J. C., Rubin, G. D., & Brundage, S. I. (2008). CT angiography effectively evaluates extremity vascular trauma. The American surgeon, 74(2), 103-7.
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  Traditionally, conventional arteriography is the diagnostic modality of choice to evaluate for arterial injury. Recent technological advances have resulted in multidetector, fine resolution computed tomographic angiography (CTA). This study examines CTA for evaluation of extremity vascular trauma compared with conventional arteriography. Our hypothesis is that CTA provides accurate and timely diagnosis of peripheral vascular injuries and challenges the gold standard of arteriogram. Traumatic extremity injuries over a 5-year period were identified using a Level I trauma center registry and radiology database. Information collected included patient demographics, mechanism, imaging modality, vascular injuries, management, and follow-up. Two thousand two hundred and fifty-one patients were identified with extremity trauma. Twenty-four patients were taken directly to the operating room for evaluation and management of vascular injuries. Fifty-two underwent vascular imaging. Fourteen patients had conventional arteriograms with 13 abnormal studies: 7 were managed operatively, 2 embolized, and 4 observed. Thirty-eight patients underwent CTA with 17 abnormal scans: 9 were managed operatively, 3 embolized, and 5 observed. There were no false negatives or missed injuries. CTA provides accurate peripheral vascular imaging while additionally offering advantages of noninvasiveness and immediate availability. Secondary to these advantages, CTA has supplanted arteriography for initial radiographic evaluation of peripheral vascular injuries at our Level I trauma center. This study supports CTA as an effective alternative to conventional arteriography in assessing extremity vascular trauma.
• Pu, J., Roos, J., Yi, C. A., Napel, S., Rubin, G. D., & Paik, D. S. (2008). Adaptive border marching algorithm: automatic lung segmentation on chest CT images. Computerized medical imaging and graphics : the official journal of the Computerized Medical Imaging Society, 32(6), 452-62.
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  Segmentation of the lungs in chest-computed tomography (CT) is often performed as a preprocessing step in lung imaging. This task is complicated especially in presence of disease. This paper presents a lung segmentation algorithm called adaptive border marching (ABM). Its novelty lies in the fact that it smoothes the lung border in a geometric way and can be used to reliably include juxtapleural nodules while minimizing oversegmentation of adjacent regions such as the abdomen and mediastinum. Our experiments using 20 datasets demonstrate that this computational geometry algorithm can re-include all juxtapleural nodules and achieve an average oversegmentation ratio of 0.43% and an average under-segmentation ratio of 1.63% relative to an expert determined reference standard. The segmentation time of a typical case is under 1min on a typical PC. As compared to other available methods, ABM is more robust, more efficient and more straightforward to implement, and once the chest CT images are input, there is no further interaction needed from users. The clinical impact of this method is in potentially avoiding false negative CAD findings due to juxtapleural nodules and improving volumetry and doubling time accuracy.
• Raman, R., Raman, B., Napel, S., & Rubin, G. D. (2008). Semiautomated quantification of the mass and distribution of vascular calcification with multidetector CT: method and evaluation. Radiology, 247(1), 241-50.
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  Institutional review board approval was obtained for this HIPAA-compliant study. Informed consent was obtained for prospective evaluation in 21 asymptomatic volunteers (10 women, 11 men; mean age, 60 years) but waived for retrospective (10 patients with and five patients without disease) evaluation. Prospective validation was in phantoms. Quantification of mass and calcium distribution was performed with fast semiautomated method, without calibration. For actual versus measured mass in phantoms, R(2) was 0.98; absolute and percentage errors were 1.2 mg and 9.1%, respectively. In asymptomatic volunteers, mean interscan variability for calcium mass quantification in extracoronary arteries was 24.9 mg; mean was 991 units for Agatston scoring. In coronary arteries, mean variability was 5.5 mg; mean Agatston variability was 27.7 units. At retrospective computed tomography, mean total calcified mass was 321.3 mg. Accurate quantification of mass and distribution of calcification in simulated arteries with this method can be applied in vivo, with low interscan variability.
• Stillman, A. E., Rubin, G. D., Teague, S. D., White, R. D., Woodard, P. K., & Larson, P. A. (2008). Structured reporting: coronary CT angiography: a white paper from the American College of Radiology and the North American Society for Cardiovascular Imaging. Journal of the American College of Radiology : JACR, 5(7), 796-800.
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  With the growing use of electronic medical records, the trend of diagnostic imaging reporting is toward a more structured format. Advantages include improved quality and consistency of the reporting and ease of data mining. The essential elements of a structured report are provided and illustrated for coronary artery computed tomographic angiograms.
• Sun, S., Zhuge, F., Rosenberg, J., Steiner, R., Rubin, G., & Napel, S. (2008). Learning-enhanced simulated annealing: Method, evaluation, and application to lung nodule registration. Applied Intelligence, 28(1). doi:10.1007/s10489-007-0043-5
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  Simulated Annealing (SA) is a popular global minimization method. Two weaknesses are associated with standard SA: firstly, the search process is memory-less and therefore can not avoid revisiting regions that are less likely to contain global minimum; and secondly the randomness in generating a new trial does not utilize the information gained during the search and therefore, the search can not be guided to more promising regions. In this paper, we present the Learning-Enhanced Simulated Annealing (LESA) method to overcome these two difficulties. It adds a Knowledge Base (KB) trial generator, which is combined with the usual SA trial generator to form the new trial for a given temperature. LESA does not require any domain knowledge and, instead, initializes its knowledge base during a "burn-in" phase using random samples of the search space, and, following that, updates the knowledge base at each iteration. This method was applied to 9 standard test functions and a clinical application of lung nodule registration, resulting in superior performance compared to SA. For the 9 test functions, the performance of LESA was significantly better than SA in 8 functions and comparable in 1 function. For the lung nodule registration application, the residual error of LESA was significantly smaller than that produced by a recently published SA system, and the convergence time was significantly faster (9.3±3.2 times). We also give a proof of LESA's ergodicity, and discuss the conditions under which LESA has a higher probability of converging to the true global minimum compared to SA at infinite annealing time. © 2007 Springer Science+Business Media, LLC.
• Terashima, M., Nguyen, P. K., Rubin, G. D., Iribarren, C., Courtney, B. K., Go, A. S., Fortmann, S. P., & McConnell, M. V. (2008). Impaired coronary vasodilation by magnetic resonance angiography is associated with advanced coronary artery calcification. JACC. Cardiovascular imaging, 1(2), 167-73.
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  This study evaluated the hypothesis that impaired nitroglycerin (NTG)-induced coronary vasodilation is associated with advanced coronary atherosclerosis in asymptomatic older patients.
• Ueda, T., Fleischmann, D., Rubin, G. D., Dake, M. D., & Sze, D. Y. (2008). Imaging of the thoracic aorta before and after stent-graft repair of aneurysms and dissections. Seminars in thoracic and cardiovascular surgery, 20(4), 348-357.
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  Thoracic endovascular aortic repair (TEVAR) has become widely accepted as an important option for treatment of thoracic aortic diseases. Cross-sectional radiologic imaging plays a crucial role for evaluating a patient's candidacy for planning of the intervention and for assessment of postprocedural results and complications of TEVAR. Recent advances in imaging technologies, in part inspired by advances in stent-graft technology, have drastically changed the character and role of pre- and postprocedural imaging. Three-dimensional (3D) datasets acquired quickly by multidetector computed tomography (MDCT), angiography, or magnetic resonance angiography (MRA) allow multiplanar reformations and 3D viewing, as well as quantitative assessment of vessel lumens, walls, and surroundings. Catheter angiography, in contrast, is performed intraoperatively almost exclusively, and is no longer the gold standard for diagnostic or planning purposes. This article reviews state-of-the-art pre- and postprocedural imaging for TEVAR, especially focusing on the role of MDCT angiography.
• Brindis, R., Kramer, C., Poon, M., & Rubin, G. (2007). Reply. Journal of the American College of Cardiology, 49(16). doi:10.1016/j.jacc.2007.02.016
• Chin, A., & Rubin, G. (2007). CT Angiography of Peripheral Arterial Occlusive Disease. Techniques in Vascular and Interventional Radiology, 9(4). doi:10.1053/j.tvir.2007.02.007
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  Lower extremity computed tomography angiography (CTA) is an effective, noninvasive, and robust imaging modality that is being used increasingly to evaluate patients with peripheral arterial occlusive disease (PAOD). It is important for vascular and interventional radiologists, and vascular surgeons to be familiar with the strengths and limitations, diagnostic accuracy, and practical application of lower extremity CTA. In this article, we review the technical principles of image acquisition, visualization techniques to effectively interpret the large volumetric datasets generated, and the current practical application of lower extremity CTA with respect to PAOD. © 2006 Elsevier Inc. All rights reserved.
• Fair, J., Kiazand, A., Varady, A., Mahbouba, M., Norton, L., Rubin, G., Iribarren, C., Go, A., Hlatky, M., & Fortmann, S. (2007). Ethnic Differences in Coronary Artery Calcium in a Healthy Cohort Aged 60 to 69 Years. American Journal of Cardiology, 100(6). doi:10.1016/j.amjcard.2007.04.038
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  Measurement of coronary artery calcium (CAC) has been proposed as a screening tool, but CAC levels may differ according to race and gender. Racial/ethnic and gender distributions of CAC were examined in a randomly selected cohort of 60- to 69-year-old healthy subjects. Demographic, race/ethnicity (R/E), and clinical characteristics and assessment of CAC were collected. There were 723 white/European, 105 African-American, 73 Hispanic, and 67 East Asian subjects (597 men, 369 women) included in this analysis. Men had a significantly higher prevalence of any CAC (score >10) than women (76% vs 41%; p
• Iribarren, C., Husson, G., Go, A., Lo, J., Fair, J., Rubin, G., Hlatky, M., & Fortmann, S. (2007). Plasma leptin levels and coronary artery calcification in older adults. Journal of Clinical Endocrinology and Metabolism, 92(2). doi:10.1210/jc.2006-1138
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  Context: Leptin is associated with adiposity and insulin resistance and may play a direct role in vascular calcification. It is unclear, however, whether leptin is an independent predictor of atherosclerotic burden. Objective: The aim of this study was to examine the association between plasma leptin and coronary artery calcification (CAC) in an ethnically diverse cohort of older adult men and women free of clinical cardiovascular disease. Design: This was a cross-sectional study with data collection between January 2002 and February 2004 as part of the ADVANCE Study. Setting: The study was conducted at an integrated health care delivery system in Northern California. Participants: Participants included 949 men and women aged 60-69 yr old. Interventions: There were no interventions. Main Outcome Measure: The main outcome measure was CAC by multidetector row computed tomography. Results: In ordinal logistic regression, plasma leptin levels were positively associated with extent of CAC independently of age, race/ ethnicity, and smoking status in women (odds ratio of higher CAC for the sex-specific upper tertile vs. lower tertile = 1.81; 95% confidence interval, 1.10-3.00) but not in men (odds ratio = 1.29; 95% confidence interval = 0.89-1.86). However, this association was explained by metabolic risk factors and adiposity measures. Conclusions: Our findings support a role of leptin on vascular calcification in women but, in our sample of older adults, the association between leptin and CAC was not independent of other cardiac risk factors. Copyright © 2007 by The Endocrine Society.
• Poon, M., Rubin, G. D., Achenbach, S., Attebery, T. W., Berman, D. S., Brady, T. J., Jacobs, J. E., Hecht, H. S., Lima, J. A., & Weigold, W. G. (2007). Consensus update on the appropriate usage of cardiac computed tomographic angiography. The Journal of invasive cardiology, 19(11), 484-90.
• Sun, S., Rubin, G., Paik, D., Steiner, R., Zhuge, F., & Napel, S. (2007). Registration of lung nodules using a semi-rigid model: Method and preliminary results. Medical Physics, 34(2). doi:10.1118/1.2432073
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  The tracking of lung nodules across computed tomography (CT) scans acquired at different times for the same patient is helpful for the determination of malignancy. We are developing a nodule registration system to facilitate this process. We propose to use a semi-rigid method that considers principal structures surrounding the nodule and allows relative movements among the structures. The proposed similarity metric, which evaluates both the image correlation and the degree of elastic deformation amongst the structures, is maximized by a two-layered optimization method, employing a simulated annealing framework. We tested our method by simulating five cases that represent physiological deformation as well as different nodule shape/size changes with time. Each case is made up of a source and target scan, where the source scan consists of a nodule-free patient CT volume into which we inserted ten simulated lung nodules, and the target scan is the result of applying a known, physiologically based nonrigid transformation to the nodule-free source scan, into which we inserted modified versions of the corresponding nodules at the same, known locations. Five different modification strategies were used, one for each of the five cases: (1) nodules maintain size and shape, (2) nodules disappear, (3) nodules shrink uniformly by a factor of 2, (4) nodules grow uniformly by a factor of 2, and (5) nodules grow nonuniformly. We also matched 97 real nodules in pairs of scans (acquired at different times) from 12 patients and compared our registration to a radiologist's visual determination. In the simulation experiments, the mean absolute registration errors were 1.0±0.8 mm (s.d.), 1.1±0.7 mm (s.d.), 1.0±0.7 mm (s.d.), 1.0±0.6 mm (s.d.), and 1.1±0.9 mm (s.d.) for the five cases, respectively. For the 97 nodule pairs in 12 patient scans, the mean absolute registration error was 1.4±0.8 mm (s.d.). © 2007 American Association of Physicists in Medicine.
• Zhuge, F., Sun, S., Rubin, G., & Napel, S. (2007). A directional distance aided method for medical image segmentation. Medical Physics, 34(12). doi:10.1118/1.2804556
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  A challenging problem in image segmentation is preventing boundary leakage through poorly resolved edges because not enough local information can be provided along them. In this article, we propose a new directional distance aided image segmentation method, formulated under the level set framework, to prevent the leakage. At each evolution step, the zero level set is extracted and smoothed. For each point on the zero level set, a new directional distance (DD) term, defined as the vector starting from itself and pointing to its counterpart on the smoothed version of the zero level set, is calculated to measure its "degree of protrusion." The evolution speed of the points that are considered to be protruding out will be penalized. Other terms, e.g., curvature and gradient terms and user specified constraints, are used along with the DD term to influence the level set evolution. Our smoothing technique augments traditional Gaussian smoothing with a new antishrinkage operation. The novelty of our method is that the DD term does not depend on intensity or gradient boundaries to regulate the regional shape and, therefore, help prevent leakage and the method incorporates vertex-based curve/surface smoothing into curve evolution under the level set framework. Experimental results show that the new DDA method achieves promising results and reasonable stability in segmenting simulated objects as well as abdominal aortic aneurysms in computed tomography (CT) angiograms, in both 2D and 3D, by preventing leakage into adjacent structures while preserving local shape details. © 2007 American Association of Physicists in Medicine.
• Raman, R., Raman, B., Moss, R., Rubin, G., Mathers, L., Robinson, T., & Venkatraman, R. (2006). Fully automated system for three-dimensional bronchial morphology analysis using volumetric multidetector computed tomography of the chest. Journal of Digital Imaging, 19(2). doi:10.1007/s10278-005-9240-0
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  Recent advancements in computed tomography (CT) have enabled quantitative assessment of severity and progression of large airway damage in chronic pulmonary disease. The advent of fast multidetector computed tomography scanning has allowed the acquisition of rapid, low-dose 3D volumetric pulmonary scans that depict the bronchial tree in great detail. Volumetric CT allows quantitative indices of bronchial airway morphology to be calculated, including airway diameters, wall thicknesses, wall area, airway segment lengths, airway taper indices, and airway branching patterns. However, the complexity and size of the bronchial tree render manual measurement methods impractical and inaccurate. We have developed an integrated software package utilizing a new measurement algorithm termed mirror-image Gaussian fit that enables the user to perform automated bronchial segmentation, measurement, and database archiving of the bronchial morphology in high resolution and volumetric CT scans and also allows 3D localization, visualization, and registration. Copyright © 2006 by SCAR (Society for Computer Applications in Radiology).
• Rubin, G. (2006). European Radiology, Supplement: Preface. European Radiology, Supplement, 16(4). doi:10.1007/s10406-006-0178-1
• Rubin, G., Bradley, W., Foley, W., Herold, C., Jaramillo, D., Seeger, L., Rubin, G., Bradley, W., Foley, W., Herold, C., Jaramillo, D., & Seeger, L. (2006). Image interpretation session: 2005. Radiographics, 26(1). doi:10.1148/rg.265055962
• Zhuge, F., Rubin, G., Sun, S., & Napel, S. (2006). An abdominal aortic aneurysm segmentation method: Level set with region and statistical information. Medical Physics, 33(5). doi:10.1118/1.2193247
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  We present a system for segmenting the human aortic aneurysm in CT angiograms (CTA), which, in turn, allows measurements of volume and morphological aspects useful for treatment planning. The system estimates a rough "initial surface," and then refines it using a level set segmentation scheme augmented with two external analyzers: The global region analyzer, which incorporates a priori knowledge of the intensity, volume, and shape of the aorta and other structures, and the local feature analyzer, which uses voxel location, intensity, and texture features to train and drive a support vector machine classifier. Each analyzer outputs a value that corresponds to the likelihood that a given voxel is part of the aneurysm, which is used during level set iteration to control the evolution of the surface. We tested our system using a database of 20 CTA scans of patients with aortic aneurysms. The mean and worst case values of volume overlap, volume error, mean distance error, and maximum distance error relative to human tracing were 95.3%±1.4% (s.d.); worst case=92.9%, 3.5%±2.5% (s.d.); worst case=7.0%, 0.6±0.2 mm (s.d.); worst case=1.0 mm, and 5.2±2.3mm (s.d.); worstcase=9.6 mm, respectively. When implemented on a 2.8 GHz Pentium IV personal computer, the mean time required for segmentation was 7.4±3.6min (s.d.). We also performed experiments that suggest that our method is insensitive to parameter changes within 10% of their experimentally determined values. This preliminary study proves feasibility for an accurate, precise, and robust system for segmentation of the abdominal aneurysm from CTA data, and may be of benefit to patients with aortic aneurysms. © 2006 American Association of Physicists in Medicine.
• Chow, L., Napoli, A., Klein, M., Chang, J., & Rubin, G. (2005). Vascular mapping of the leg with multi-detector row CT angiography prior to free-flap transplantation. Radiology, 237(1). doi:10.1148/radiol.2371040675
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  PURPOSE: To retrospectively evaluate multi-detector row computed tomographic (CT) angiography in determining donor- and recipient-site arterial suitability for successful vascularized free-flap transplantation. MATERIALS AND METHODS: The institutional review board granted approval; informed consent was waived, and the study was HIPAA compliant. Lower extremities of 20 (12 male, eight female; mean age, 51 years; range, 10-84 years) patients undergoing vascularized free-flap procedures were examined at multi-detector row CT angiography. In five patients, legs were assessed as potential fibular free-flap donors for mandibular, maxillary, or radial reconstruction. In 15 patients, legs were assessed as recipient sites for free flaps. Vascular maps obtained with volume rendering, maximum intensity projections, and curved planar reformations were generated, and assessment was made in the depiction of calf vessels and presence of stenosis, occlusion, and anatomic anomaly. Findings of CT angiography, physical examination, and surgery were compared, where applicable, and successful CT-based prediction of the surgical intervention was assessed. Immediate and long-term (>70 days) viability of the graft was assessed in all patients. RESULTS: CT angiography depicted the entirety of all four major calf arteries in 29 of 32 legs scanned. In three legs, external-fixation hardware obscured some segments. There were no discrepancies between CT findings and those identified at the time of surgery. Arterial abnormalities, including stenosis, occlusion, and variant anatomy, were seen in 12 lower extremities in 10 patients. Only two were suspected on the basis of physical examination findings. In five of 20 patients, CT findings resulted in changes to the surgical plan. There was a 100% immediate viability of all grafts, which remained well vascularized between 70 days and 37 months after the procedure. CONCLUSION: Multi-detector row CT angiography provides a noninvasive means of preoperatively assessing lower extremity arteries for abnormalities, which could jeopardize graft viability or pedal arterial supply after free-flap procedures. © RSNA, 2005.
• Fleischmann, D., & Rubin, G. (2005). Quantification of intravenously administered contrast medium transit through the peripheral arteries: Implications for CT angiography. Radiology, 236(3). doi:10.1148/radiol.2363041392
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  PURPOSE: To prospectively determine the range of aortopopliteal bolus transit times in patients with moderate-to-severe peripheral arterial occlusive disease (PAOD) as a guideline for developing injection strategies for computed tomographic (CT) angiography of peripheral arteries. MATERIALS AND METHODS: The study protocol was approved by the local ethics board, and informed consent was obtained. Twenty patients with PAOD referred for CT angiography of the lower extremities were categorized into two groups. Fontaine stage IIb (group 1) and stage III or IV (group 2), and demographic information was collected. In all patients, a 16-mL test bolus was injected intravenously, and single-level dynamic acquisitions were obtained at the level of the abdominal aorta. After injection of a second 16-mL test bolus, dynamic acquisitions were obtained at the level of the knee (popliteal arteries). Aortopopliteal bolus transit times were calculated by subtracting the time to peak enhancement in the popliteal arteries from that in the aorta. Aortopopliteal transit speeds also were derived. Transit times and speeds were compared graphically between clinical stage groups. The time required for the contrast medium to enhance the entire peripheral arterial tree in patients with PAOD was estimated by using linear extrapolation. RESULTS: Sixteen men and four women with a mean age of 69 years (range, 49-86 years) were included. Twelve patients were included in group 1, and eight patients, in group 2. Aortopopliteal bolus transit times ranged from 4 to 24 seconds (median, 8 seconds) in all subjects, which corresponded to bolus transit speeds of 177 and 29 mm/sec, respectively. Wide overlap of transit times and transit speeds was observed between clinical stage groups. The estimated time needed for the bolus to enhance the entire peripheral arterial tree was 6-39 seconds. CONCLUSION: Aortopopliteal bolus transit times differ widely among patients and may be substantially delayed in all patients with PAOD. Empirical injection protocols should include an injection duration of 35 seconds or more, as well as an increased scanning delay, with table speeds of more than 30 mm/sec. © RSNA, 2005.
• Hundt, W., Siebert, K., Wintersperger, B., Becker, C., Knez, A., Reiser, M., & Rubin, G. (2005). Assessment of global left ventricular function: Comparison of cardiac multidetector-row computed tomography with angiocardiography. Journal of Computer Assisted Tomography, 29(3). doi:10.1097/01.rct.0000160426.41014.b1
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  Objective: Evaluation of left ventricular function using electrocardiogram (ECG)-gated multidetector row CT (MDCT) by using 3 different volumetric assessment methods in comparison to assessment of the left ventricular function by invasive ventriculography. Methods: Thirty patients with suspected or known coronary artery disease underwent MDCT coronary angiography with retrospective ECG cardiac gating. Raw data were reconstructed at the end-diastolic and end-systolic periods of the heart cycle. To calculate the volumes of the left ventricle, 3 methods were applied: The 3-dimensional data set (3D), the geometric hemisphere cylinder (HC), and the geometric biplane ellipsoid (BE) methods. End-diastolic volumes (EDV), end-systolic volumes (ESV), the stroke volumes (SV), and ejection fractions (EF) were calculated. The left ventricular volumetric data from the 3 methods were compared with measurements from left ventriculography (LVG). Results: The best results were obtained using the 3D method; EDV (r = 0.73), ESV (r = 0.88), and EF (r = 0.76) correlated well with the LVG data. The EDV volumes did not differ significantly between LVG and the 3D method (P = 0.24); however, ESV, SV, and EF differed significantly. The ESV were significantly overestimated (P < 0.01), leading to an underestimation of the SV (P < 0.01) and the EF (P < 0.01). The HC method resulted in the greatest overestimation of the volumes. The EDV and the ESV were 31.8 ± 37.6% and 136.4 ± 92.9% higher than the EDV and ESV volumes obtained by LVG. Bland-Altman analysis showed systematic overestimation of the ESV using the HC method. Conclusion: MDCT with retrospective cardiac ECG gating allows the calculation of left ventricular volumes to estimate systolic function. The 3D method had the highest correlation with LVG. However, the overestimation of the ESV is significant, which led to an underestimation of the SV and the EF. Copyright © 2005 by Lippincott Williams & Wilkins.
• Kwan, S., Partik, B., Zinck, S., Chan, F., Kee, S., Leung, A., Voracek, M., & Rubin, G. (2005). Primary interpretation of thoracic MDCT images using coronal reformations. American Journal of Roentgenology, 185(6). doi:10.2214/AJR.04.1335
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  OBJECTIVE. The objective of this study was to evaluate the accuracy and efficiency of primary interpretation of thoracic MDCT using coronal reformations as compared with transverse images. SUBJECTS AND METHODS. Fifty patients (18 females, 32 males; age range, 15-93 years; mean age, 63.6 years) underwent 4-MDCT of the chest (detector width, 1 mm; beam pitch, 1.5). Contrast material was administered in 20 of the 50 patients. Coronal and transverse sections were reformatted into 5-mm-thick sections at 3.5-mm intervals. All available image and clinical data consensually reviewed by two thoracic radiologists served as the reference standard. Subsequently, three other thoracic radiologists independently evaluated reformatted coronal and transverse images at two separate review sessions. Each image set was assessed in 58 categories for abnormalities of the lungs, mediastinum, pleura, chest wall, diaphragm, abdomen, and skeleton. Interpretation times and number of images assessed were recorded. Sensitivity, specificity, and interobserver concordance were calculated. Differences in mean sensitivities and specificities were evaluated with Wilcoxon's signed rank test. RESULTS. The most common findings identified were pulmonary nodules (n = 73, transverse images; n = 72, coronal images) and emphysema (n = 45, transverse; n = 40, coronal). The mean detection sensitivity of all lesions was significantly (p = 0.001) lower on coronal (44% ± 26% [SD]) than on transverse (51% ± 22%) images, whereas the mean detection specificity was significantly (p = 0.005) higher (96% ± 5% vs 95% ± 6%, respectively). Reporting findings for significantly (p < 0.001) fewer coronal images (mean, 63.0 ± 4.6 images) than transverse images (mean, 91.9 ± 8.8 images) took significantly (p = 0.025) longer (mean, 263 ± 56 sec vs 238 ± 45 sec, respectively). CONCLUSION. Primary interpretation of thoracic MDCT is less sensitive and more time-consuming using 5-mm-thick coronal reformations as compared with transverse images. © American Roentgen Ray Society.
• Roos, J., Hellinger, J., Hallet, R., Fleischmann, D., Zarins, C., & Rubin, G. (2005). Detection of endograft fractures with multidetector row computed tomography. Journal of Vascular Surgery, 42(5). doi:10.1016/j.jvs.2005.07.009
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  Delayed endograft metallic strut failures detected in vivo with multidetector row computed tomography (MDCT) are reported in two patients who underwent endovascular abdominal aortic aneurysm repair with AneuRx and Talent endografts. In both instances, nitinol fractures were associated with proximal migration and type I endoleak. In both cases, the metallic strut fractures were detected with transverse sections from 16-channel MDCT angiograms and confirmed by using volume rendering. These cases highlight the previously unreported ability of thin-section, high-resolution MDCT angiography to detect endograft strut fractures. Copyright © 2005 by The Society for Vascular Surgery.
• Sherbondy, A., Holmlund, D., Rubin, G., Schraedley, P., Winograd, T., & Napel, S. (2005). Alternative input devices for efficient navigation of large CT angiography data sets. Radiology, 234(2). doi:10.1148/radiol.2342032017
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  PURPOSE: To compare devices for the task of navigating through large computed tomographic (CT) data sets at a picture archiving and communication system workstation. MATERIALS AND METHODS: The institutional review board approved this study, and all subjects provided informed consent. Five radiologists were asked to find 25 different vascular targets in three CT angiography data sets (average number of sections, 1025) by using several devices (trackball, tablet, jog-shuttle wheel, and mouse). For each trial, the total time to acquire the targets (T1) was recorded. A secondary study in which 13 nonradiologists performed seven trials with an artificial target inserted at a random location in the same image data was also performed. For each trial, the following items were recorded: time until first target sighting (t2), time to manipulate the device after seeing the target, sections traversed during t2 (dl), time from first sight to target acquisition (t4), sections traversed during t4 (d2), and total trial time. Statistical analysis involved repeated-measures analysis of variance (ANOVA) and pairwise comparisons. RESULTS: Repeated-measures ANOVA revealed that the device used had a significant (P < .05) effect on 71. Pairwise comparisons revealed that the trackball was significantly slower than the tablet (P < .05) and marginally slower than the jog-shuttle wheel (P < .10). Further repeated-measures ANOVA for each secondary outcome measure revealed significant differences between devices for all outcome measures (P < .005). Pairwise comparisons revealed the trackball to be significantly slower than the other devices in all measures (P < .05). The trackball was significantly (P < .05) more accurate than the other devices for d1 and d2. CONCLUSION: The trackball may not be the optimal device for navigation of large CT angiography data sets; the use of other existing devices may improve the efficiency of interpretation of these sets. © RSNA, 2005.
• Bogdan, M., Klein, M., Rubin, G., McAdams, T., & Chang, J. (2004). CT angiography in complex upper extremity reconstruction. Journal of Hand Surgery, 29(5). doi:10.1016/j.jhsb.2004.04.006
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  Computed tomography angiography is a new technique that provides high-resolution, three-dimensional vascular imaging as well as excellent bone and soft tissue spatial relationships. The purpose of this study was to examine the use of computed tomography angiography in planning upper extremity reconstruction. Seventeen computed tomography angiograms were obtained in 14 patients over a 20-month period. All studies were obtained on an outpatient basis with contrast administered through a peripheral vein. All the studies demonstrated the pertinent anatomy and the intraoperative findings were as demonstrated in all cases. Information from two studies significantly altered pre-operative planning. The average charge for computed tomography angiography was $1,140, compared to $3,900 for traditional angiography. © 2004 The British Society for the Hand. Published by Elsevier Ltd. All rights reserved.
• Funabashi, N., Kobayashi, Y., Kudo, M., Asano, M., Teramoto, K., Komuro, I., & Rubin, G. (2004). New method of measuring coronary diameter by electron-beam computed tomographic angiography using adjusted thresholds determined by calibration with aortic opacity. Circulation Journal, 68(8). doi:10.1253/circj.68.769
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  Background: In a previous study the adjusted thresholds at which the diameters of coronary arteries determined by enhanced electron-beam computed tomography (CT) scans are equal to the corresponding quantitative coronary angiography measurements were analyzed, and their correlation with maximum CT values for the vessel short axes was determined. A rapid accurate method for such measurements was sought by substituting maximum CT values for the descending aorta in the corresponding axial images for those for the short axes. Methods and Results: In 8 patients, 179 sites were measured. Means (±SD) of adjusted thresholds and the maximum CT values for vessel short axes and the descending aorta in the corresponding axial images for all vessels were 108±66, 227±80, and 363±75 Hounsfield Unit (HU), respectively. Adjusted thresholds correlated with the maximum CT values for the corresponding vessel short axes and the descending aorta in the corresponding axial images, with R2=0.55, 0.33, p
• Hiatt, M., & Rubin, G. (2004). Surveillance for endoleaks: How to detect all of them. Seminars in Vascular Surgery, 17(4). doi:10.1053/j.semvascsurg.2004.09.003
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  Endovascular aneurysm repair has proven to be a valuable alternative to open repair in selected patients. This less invasive procedure, however, requires long-term surveillance for its own set of potential complications, including perigraft leakage, or endoleak. This article focuses on the detection of these leaks, first defining and classifying endoleaks and then describing various means of detecting them, including computed tomographic angiography, magnetic resonance angiography, color-flow duplex ultrasonography, and conventional angiography. © 2004 Elsevier Inc. All rights reserved.
• Karanas, Y., Antony, A., Rubin, G., Chang, J., Karanas, Y., Antony, A., Rubin, G., & Chang, J. (2004). Preoperative CT angiography for free fibula transfer. Microsurgery, 24(2). doi:10.1002/micr.20009
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  The role of preoperative imaging prior to free fibula flap harvest remains controversial. The standard method of preoperative imaging has been arteriography. However, arteriography is associated with known risks and potential complications to the patient. Alternatives to traditional angiography have been sought to attempt to reduce these risks. CT angiography is a noninvasive imaging modality that can accurately assess the arterial and venous circulation, while providing images equal to those of traditional angiography. CT angiography was used in 7 patients prior to free fibula flap harvest. There were no complications from the CT angiogram or the fibula harvest. We describe our use of CT angiography for vascular imaging of the lower extremity prior to free fibula harvest. © 2004 Wiley-Liss, Inc.
• Paik, D., Beaulieu, C., Rubin, G., Acar, B., Jeffrey, R., Yee, J., Dey, J., & Napel, S. (2004). Surface normal overlap: A computer-aided detection algorithm with application to colonic polyps and lung nodules in helical CT. IEEE Transactions on Medical Imaging, 23(6). doi:10.1109/tmi.2004.826362
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  We developed a novel computer-aided detection (CAD) algorithm called the surface normal overlap method that we applied to colonic polyp detection and lung nodule detection in helical computed tomography (CT) images. We demonstrate some of the theoretical aspects of this algorithm using a statistical shape model. The algorithm was then optimized on simulated CT data and evaluated using a per-lesion cross-validation on 8 CT colonography datasets and on 8 chest CT datasets. It is able to achieve 100% sensitivity for colonic polyps 10 mm and larger at 7.0 false positives (FPs)/dataset and 90% sensitivity for solid lung nodules 6 mm and larger at 5.6 FP/dataset.
• Funabashi, N., Kobayashi, Y., Perlroth, M., & Rubin, G. (2003). Coronary artery: Quantitative evaluation of normal diameter determined with electron-beam CT compared with cine coronary angiography - Initial experience. Radiology, 226(1). doi:10.1148/radiol.2261011211
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  Eight male heart transplant recipients underwent contrast material-enhanced electron-beam computed tomographic angiography. Coronary artery diameters measured with fixed thresholds and adaptive line density profile (LDP) methods were calculated relative to findings at quantitative coronary angiography. Variation with fixed-threshold methods was significantly greater than that with LDP methods because of variations in vessel enhancement. Thus, more accurate measurements of vessel diameter were obtained with LDP methods. © RSNA, 2002.
• Klein, M., Karanas, Y., Chow, L., Rubin, G., & Chang, J. (2003). Early experience with computed tomographic angiography in microsurgical reconstruction. Plastic and Reconstructive Surgery, 112(2). doi:10.1097/01.prs.0000070990.97274.fa
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  Preoperative angiography is frequently used in the planning of microsurgical reconstruction. However, several potentially devastating complications can result from angiography, including arterial occlusion and pseudoaneurysm. Computed tomographic angiography is a relatively new technique that can provide detailed information about vascular anatomy as well as soft and bony tissue without the risks of traditional angiography. In addition, three-dimensional image reconstruction uniquely demonstrates anatomical relationships among blood vessels, bones, and soft tissue. Fourteen computed tomographic angiograms were obtained in 10 patients undergoing microsurgical reconstruction of the head and neck, lower extremity, or upper extremity. The average patient age was 46.9 years (range, 22 to 67 years). Charges related to the computed tomographic procedure were compared with those of conventional preoperative imaging for microsurgical repair. At our institution, the average computed tomographic angiogram charge was $1140, whereas the average charge for traditional arteriography was $3900. When compared with intraoperative evaluation, computed tomographic angiograms demonstrated clinically relevant surgical anatomy. No complications were noted for the radiographic procedure or after free flap reconstruction. Computed tomographic angiography provides high-resolution, three-dimensional arterial, venous, and soft-tissue imaging without the risks of traditional angiogram and at a lower cost.
• Raman, R., Napel, S., & Rubin, G. (2003). Curved-slab maximum intensity projection: Method and evaluation. Radiology, 229(1). doi:10.1148/radiol.2291020370
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  The authors developed and evaluated a method to produce curved-slab maximum intensity projections (MIPs) through blood vessels that semiautomatically excludes soft tissue and bone. Results obtained with the algorithm were compared with those obtained with rectangular-slab MIPs by using computed tomographic (CT) data from four patients with abdominal aortic aneurysms. Curved-slab MIPs exhibited increased mean vessel-to-perivascular tissue contrast of 55.1 HU (36%), allowed a 10% increase in contrast-to-noise ratio, and decreased apparent vessel narrowing by 0.12-1.09 mm, without increasing processing time. Curved-slab MIPs may also include multiple vessels in a single image, thereby improving interpretation efficiency by reducing the number of MIPs required in these patients from eight to three. © RSNA, 2003.
• Rubin, G. (2003). CT angiography of the thoracic aorta. Seminars in Roentgenology, 38(2). doi:10.1016/s0037-198x(03)00010-5
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  Nine years after its introduction, spiral or helical CTA is being embraced as an important noninvasive tool for imaging the thoracic aorta and its branches. The high degree Of accessibility and ease with which the studies are performed make it a viable alternative to aortography. Once familiar with the principles of CTA, the acquisition phase of the examination can be completed in as little as 15 minutes. Nevertheless, important challenges remain for CTA. The capabilities of MDCT to acquire thinner sections in shorter scan times have resulted in a veritable explosion of imaging data for radiologists to analyze. In this environment, efficient image processing workstations and software is critical to improving our ability to efficiently interpret these volumetric CT data. Finally, helical CT technology is far from static. Every year, new advances in engineering bring better image quality, improved resolution, and faster scan times. As medical imagers, we must not become complacent but rather constantly challenge ourselves to consider how we might further improve on our utilization of CT equipment to maximize the collection of information relevant to diagnosis and therapy.
• Shiffman, S., Rubin, G., Schraedley-Desmond, P., & Napel, S. (2003). Semiautomated segmentation of blood vessels using ellipse-overlap criteria: Method and comparison to manual editing. Medical Physics, 30(10). doi:10.1118/1.1604731
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  Two-dimensional intensity-based methods for the segmentation of blood vessels from computed-tomography-angiography data often result in spurious segments that originate from other objects whose intensity distributions overlap with those of the vessels. When segmented images include spurious segments, additional methods are required to select segments that belong to the target vessels. We describe a method that allows experts to select vessel segments from sequences of segmented images with little effort. Our method uses ellipse-overlap criteria to differentiate between segments that belong to different objects and are separated in plane but are connected in the through-plane direction. To validate our method, we used it to extract vessel regions from volumes that were segmented via analysis of isolabel-contour maps, and showed that the difference between the results of our method and manually-edited results was within inter-expert variability. Although the total editing duration for our method, which included user-interaction and computer processing, exceeded that of manual editing, the extent of user interaction required for our method was about a fifth of that required for manual editing. © 2003 American Association of Physicists in Medicine.
• Filis, K., Arko, F., Rubin, G., Raman, B., Fogarty, T., & Zarins, C. (2002). Aortoiliac angulation and the need for secondary procedures to secure stent graft fixation: Which angle is important?. International Angiology, 21(4).
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  Background. The purpose of this study was to quantify the degree of aortoiliac tortuosity and determine the relationship between aortoiliac angulation and the need for a secondary procedure following endovascular repair. Methods. Among 206 patients treated with the AneuRx stent graft, 3-year follow up data were available in 71 patients. Twenty eight patients without duplex and CT angiograms (CT angiography) on follow-up were excluded. The anatomy of the preoperative proximal aortic neck was evaluated using 3D-CT angiography reconstructed images in: a) Group I: 15 patients who required secondary procedures and b) Group II: 18 patients without any endovascular leak during follow up. The groups did not differ in age (72.9±6.1 versus 73.3±9.1) or aneurysm diameter (60.1±9.1 versus 60.5±10.1). In order to determine the aortoiliac tortuosity, we measured: a) the suprarenal aorta-infrarenal aortic neck angle: angle of the aorta at the level of the renal arteries, b) infrarenal aortic neck-aneurysm angle: angle of the aorta at the start of aneurysm, c) right iliac angle, d) left iliac angle, e) aortic neck length, f) aortic neck diameter. Results. Computer-based measurements on 3D-CT angiography reconstructed images were: a) suprarenal aorta-infrarenal aortic neck angle: group I: (22.6±16.2), group II: (11.9±6.9), p
• Lee, W., Rubin, G., Johnson, B., Arko, F., Fogarty, T., & Zarins, C. (2002). "Pseudoendoleak" - Residual intrasaccular contrast after endovascular stent-graft repair. Journal of Endovascular Therapy, 9(1). doi:10.1583/1545-1550(2002)009<0119:pricae>2.0.co;2
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  Purpose: To present a unique demonstration of postoperative perigraft contrast masquerading as an endoleak following endovascular abdominal aortic aneurysm (AAA) repair. Case Report: A 66-year-old man underwent endovascular stent-graft repair of a 4.6-cm infrarenal AAA. The procedure was uncomplicated, and intraoperative completion angiography demonstrated good proximal and distal fixation of the stent-graft without an endoleak. A spiral computed tomographic (CT) angiogram obtained on postoperative day 2 revealed a large amount of extrastent contrast along the posterior aspect of the aneurysm sac. This defect had the appearance of an endoleak, but it was also present on the non-contrast images. A color-flow duplex examination performed on the same day showed a widely patent stent-graft with no evidence of extrastent flow. Conclusions: Contrast trapped in the aneurysm sac during endovascular aneurysm repair may be misinterpreted as an endoleak on postprocedural CT scans. "Pseudoendoleaks" can be distinguished from true endoleaks by examination of prebolus, noncontrast CT images, as well as by duplex ultrasound scanning.
• Prokesch, R., Coulam, C., Chow, L., Bammer, R., & Rubin, G. (2002). CT angiography of the subclavian artery: Utility of curved planar reformations. Journal of Computer Assisted Tomography, 26(2). doi:10.1097/00004728-200203000-00007
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  Despite advances in the diagnosis and treatment of peripheral vascular occlusive disease, an ever-aging population continues to provide scores of new cases requiring medical care. While traditional angiography has been the mainstay of diagnosis for many years, newer, less invasive techniques such as CT angiography with three-dimensional reformation are rapidly establishing themselves as first-line diagnostic modalities. We present a case of severe left subclavian artery stenosis that demonstrates the utility of curved planar reformation in providing a concise visual summary of the pertinent anatomy and abnormalities.
• Raman, R., Napel, S., Beaulieu, C., Bain, E., Jeffrey, R., & Rubin, G. (2002). Automated generation of curved planar reformations from volume data: Method and evaluation. Radiology, 223(1). doi:10.1148/radiol.2231010441
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  The authors developed and evaluated a method to automatically create interactive vascular curved planar reformations with computed tomographic (CT) angiographic data. The method decreased user interaction time by 86%, from 15 to 2 minutes. Expert reviewers were asked to indicate their confidence in differentiating automatically created images from clinical-quality manually produced images. The area under the receiver operating characteristic curve was 0.45 (95% Cl: 0.39, 0.51), and a test of equivalency indicated that reviewers could not distinguish between images. They also graded image quality as equivalent to that with manual methods and found fewer artifacts on automatically created images. Automatic methods rapidly produce curved planar reformations of equivalent quality with reduced time and effort. © RSNA, 2002.
• Veith, F., Baum, R., Ohki, T., Amor, M., Adiseshiah, M., Blankensteijn, J., Buth, J., Chuter, T., Fairman, R., Gilling-Smith, G., Harris, P., Hodgson, K., Hopkinson, B., Ivancev, K., Katzen, B., Lawrence-Brown, M., Meier, G., Malina, M., Makaroun, M., , Parodi, J., et al. (2002). Nature and significance of endoleaks and endotension: Summary of opinions expressed at an international conference. Journal of Vascular Surgery, 35(5). doi:10.1067/mva.2002.123095
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  Objective: Endoleaks and endotension are critically important complications of some endovascular aortic aneurysm repairs (EVARs). For the resolution of controversial issues and the determination of areas of uncertainty relating to these complications, a conference of 27 interested leaders was held on November 20, 2000. Methods: These 27 participants (21 vascular surgeons, five interventional radiologists, one cardiologist) had previously answered 40 key questions on endoleaks and endotension. At the conference, these 40 questions and participant answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus (prevailing opinion), or disagreement. Results: Conference discussion added two modified questions for a total of 42 key questions for the participants. Interestingly, consensus was reached on the answers to 24 of 42 or 57% of the questions, and near consensus was reached on 14 of 42 or 33% of the questions. Only with the answers to four of 42 or 10% of the questions was there persistent controversy or disagreement. Conclusion: The current endoleak classification system with some important modifications is adequate. Types I and II endoleak occur after 0 to 10% and 10% to 25% of EVARs, respectively. Many (30% to 100%) type II endoleaks will seal and have no detrimental effect, which never or rarely occurs with type I endoleaks. Not all endoleaks can be visualized with any technique, and increased pressure (endotension) can be transmitted through clot. Aneurysm pulsatility after EVAR correlates poorly with endoleaks and endotension. An enlarging aneurysm after EVAR mandates surgical or interventional treatment. These and other conclusions will help to resolve controversy and aid in the management of these vexing complications and should also point the way to future research in this field. Copyright © 2002 by The Society for Vascular Surgery and The American Association for Vascular Surgery.
• Wolf, Y., Tillich, M., Lee, W., Fogarty, T., Zarins, C., & Rubin, G. (2002). Changes in aneurysm volume after endovascular repair of abdominal aortic aneurysm. Journal of Vascular Surgery, 36(2). doi:10.1067/mva.2002.126085
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  Objective: The purpose of this study was to define changes in aneurysm volume after endovascular repair of abdominal aortic aneurysm. Methods: A total of 154 consecutive patients who underwent endovascular repair of abdominal aortic aneurysm with the Medtronic AneuRx stent graft at Stanford University Hospital were evaluated. During a mean follow-up period of 15.8 ± 11.3 months, serial computerized measurements of aneurysm volume and orthogonal maximal diameter were performed on helical computed tomographic scan data sets and maximal transverse diameter was measured manually from transverse computed tomographic images. Aortoiliac length (renal to hypogastric artery origin) was measured along the median luminal centerline and along the straight line. Results: Aneurysm volume increased immediately after endovascular repair (from 180.2 ± 69.9 mL to 187.9 ± 71.6 mL; P < .001), but orthogonal and transverse diameter and aortoiliac length did not change significantly. During the follow-up period, mean volume decreased to 171.9 ± 70.2 mL (P < .05) and straight-line and centerline aortoiliac length remained unchanged from preoperative values. Overall, volume decreased at a rate of 1.7 ± 5.9 mL/mo (P < .001). During periods without endoleak, the rate of decrease was 3.2 ± 5.5 mL/mo (P < .001), and during periods with endoleak, aneurysm volume increased at a rate of 2.0 ± 5.3 mL/mo (P < .005), without a difference between types of endoleak. Predictive values for the presence of endoleak were similar for transverse and orthogonal diameter and volume. Logistic regression analysis showed volume to be most closely associated with the presence of endoleak. Conclusion: Aneurysm volume increases immediately after endovascular repair. After repair, aneurysm volume gradually decreases and aortoiliac length remains unchanged. Changes in volume parallel changes in maximal aneurysm diameter, and their association with the presence of an endoleak does not appear to be appreciably stronger.
• Arko, F., Rubin, G., Johnson, B., Hill, B., Fogarty, T., & Zarins, C. (2001). Type-II endoleaks following endovascular AAA repair: Preoperative predictors and long-term effects. Journal of Endovascular Therapy, 8(5). doi:10.1583/1545-1550(2001)008<0503:tiefea>2.0.co;2
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  Purpose: To determine the significance of persistent type-II endoleaks and whether they can be predicted preoperatively in patients with abdominal aortic aneurysms (AAA). Methods: The charts of all AAA patients treated with the AneuRx stent-graft at a single center from 1996 to 1998 were reviewed. Patients with 2 lumbar arteries on preoperative CT angiography are at higher risk for persistent type-II endoleaks.
• Coulam, C., & Rubin, G. (2001). Acute aortic abnormalities. Seminars in Roentgenology, 36(2). doi:10.1053/sroe.2001.23049
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  Aneurysm and type B dissections account for most acute abdominal aortic abnormalities. The postsurgical aorta deserves special attention owing to the risk of complications. Most aortic abnormalities presenting acutely are emergencies that carry a high risk of mortality, and imaging plays a critical role in patient evaluation. Modern helical CT scanners provide excellent spatial resolution, are readily available, and allow for rapid imaging. For these reasons, helical CT angiography is the imaging modality of choice for initial evaluation of the acute aorta.
• Fleischmann, D., Hastie, T., Dannegger, F., Paik, D., Tillich, M., Zarins, C., & Rubin, G. (2001). Quantitative determination of age-related geometric changes in the normal abdominal aorta. Journal of Vascular Surgery, 33(1). doi:10.1067/mva.2001.109764
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  Purpose: We conducted a novel quantitative three-dimensional analysis of computed tomography (CT) angiograms to establish the relationship between aortic geometry and age, sex, and body surface area in healthy subjects. Methods: Abdominal helical CT angiograms from 77 healthy potential renal donors (33 men/44 women; mean age, 44 years; age range, 19-67 years) were selected. In each dataset, orthonormal cross-sectional area and diameter measurements were obtained at 1-mm intervals along the automatically calculated central axis of the abdominal aorta. The aorta was subdivided into six consecutive anatomic segments (supraceliac, supramesenteric, suprarenal, inter-renal, proximal infrarenal, and distal infrarenal). The interrelated effects of anatomic segment, age, sex, and body surface area on cross-sectional dimensions were analyzed with linear mixed-effects and varying-coefficient statistical models. Results: We found that significant effects of sex and of body surface area on aortic diameters were similar at all anatomic levels. The effect of age, however, was interrelated with anatomic position, and gradually decreasing slopes of significant diameter-versus-age relationships along the aorta, which ranged from 0.14 mm/y (P < .0001) proximally to 0.03 mm/y (P = .013) distally in the abdominal aorta, were shown. Conclusion: The abdominal aorta undergoes considerable geometric changes when a patient is between 19 and 67 years of age, leading to an increase of aortic taper with time. The hemodynamic consequences of this geometric evolution for the development of aortic disease still need to be established.
• Funabashi, N., & Rubin, G. (2001). Direct identification of patency achieved by a bi-directional Glenn shunt procedure - Images by volume rendering using electron-beam computed tomography. Japanese Circulation Journal, 65(5). doi:10.1253/jcj.65.457
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  The present study aimed to identify the patency achieved by a bi-directional Glenn shunt procedure by shaded volume rendering (VR) images using electron-beam computed tomography (EBCT). A Damus Kay-Stanzel type procedure was performed on a female with hypoplastic left heart syndrome who later received a bi-directional Glenn shunt to increase pulmonary blood flow. In considering the characteristics of the bi-directional Glenn shunt procedure, in which the superior vena cava is connected to the right pulmonary artery, an early phase acquisition protocol with injection of contrast material from the right cubital vein using the step volume scan mode of EBCT was planned to acquire blood flow information. Excellent spatial resolution volume data of the heart and great vessels was obtained from which 3-dimensional images were made. Bi-directional Glenn shunt flow could be observed directly and the complex morphology and relationships between adjacent structures were revealed by 3-dimensional VR imaging. The combination of EBCT and VR can provide useful information to evaluate congenital heart diseases.
• Funabashi, N., Kobayashi, Y., & Rubin, G. (2001). Three-dimensional images of coronary arteries after heart transplantation using electron-beam computed tomography data with volume rendering.. Circulation, 103(5). doi:10.1161/01.cir.103.5.e25
• Funabashi, N., Kobayashi, Y., & Rubin, G. (2001). Utility of three-dimensional volume rendering images using electron-beam computed tomography to evaluate possible causes of ischemia from an anomalous origin of the right coronary artery from the left sinus of Valsalva. Japanese Circulation Journal, 65(6). doi:10.1253/jcj.65.575
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  The present study evaluated the usefulness of 3-dimensional volume rendering (VR) images using electron-beam computed tomography (EBCT) in determining the possible causes of ischemia resulting from the anomalous origin of the right coronary artery (RCA) from the left sinus of Valsalva, which coursed between the ascending aorta and pulmonary trunk. Such anomalies could cause ischemia or sudden death without obstructive coronary artery disease. The suggested mechanism is either compression causing closure of the slit-like orifice of the anomalous artery as the aorta dilates with exertion or compression of the anomalous artery by the aorta and pulmonary trunk as it courses between these 2 arteries, which dilate with exercise. A 17-year-old male underwent EBCT coupled with a 100-ml intravenous injection of iodinated contrast medium. Data were reconstructed into 3-dimensional images through VR to evaluate the shape of the orifice and the spatial relationship of the RCA, ascending aorta and pulmonary trunk. Perspective VR showed the shape of the orifice of the left main trunk, which was not slit-like, and cut-plane VR showed the spatial relationship of both the lumen and the surface of the RCA, ascending aorta and pulmonary trunk, providing information on whether the ascending aorta or pulmonary trunk would compress the RCA and cause ischemia.
• Jones, T., Kaplan, R., Lane, B., Atlas, S., & Rubin, G. (2001). Single- versus multi-detector row CT of the brain: Quality assessment. Radiology, 219(3). doi:10.1148/radiology.219.3.r01jn47750
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  PURPOSE: To assess the quality of brain computed tomographic (CT) studies obtained with a four-channel multi-detector row CT scanner compared with those obtained with a single-detector row CT scanner. MATERIALS AND METHODS: Forty-seven patients referred for brain CT were imaged with both single- and multi-detector row scanners. Single-detector row CT images were acquired by using a 5-mm-collimated beam in the transverse mode. Multi-detector row CT images were acquired in four simultaneous 2.5-mm-thick sections, which were combined in projection space to create two contiguous 5-mm-thick sections. Two neuroradiologists blinded to the acquisition technique independently evaluated the CT image pairs, which were presented in a stacked mode on two adjacent monitors. Each study was graded by using a five-point scale for posterior fossa artifact, overall image quality, and overall preference. RESULTS: Multi-detector row CT studies were acquired 1.8 times faster than single-detector row CT studies (0.92 vs 0.52 section per second). Multi-detector row CT posterior fossa artifact was less than single-detector row CT posterior fossa artifact in 87 (93%) of 94 studies. Overall preference was expressed for multi-detector row CT in 84 (89%) of 94 studies. The differences in mean posterior fossa artifact scores (P < .001) and mean overall image quality scores (P = .001) were significant. CONCLUSION: Brain CT images obtained with multi-detector row CT resulted in significantly less posterior fossa artifact and were preferred to single-detector row CT images.
• Lee, W., Rubin, G., Arko, F., Hill, B., & Zarins, C. (2001). Endovascular stent graft repair of an infrarenal abdominal aortic aneurysm with a horseshoe kidney. Circulation, 103(16). doi:10.1161/01.cir.103.16.2126
• Leung, A., Rubin, G., Kee, S., Mindelzun, R., Stark, P., Wexler, L., Plevritis, S., Betts, B., & Miró, S. (2001). Digital storage phosphor chest radiography: An ROC study of the effect of 2K versus 4K matrix size on observer performance. Radiology, 218(2). doi:10.1148/radiology.218.2.r01fe26527
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  PURPOSE: To compare observer performance in the detection of abnormalities on 1,760 x 2,140 matrix (2K) and 3,520 x 4,280 matrix (4K) digital storage phosphor chest radiographs. MATERIALS AND METHODS: One hundred sixty patients who underwent dedicated computed tomography (CT) of the thorax were prospectively recruited into the study. Posteroanterior and lateral computed radiographs of the chest were acquired in each patient and printed in 2K and 4K formats. Six radiologists independently analyzed the hard-copy images and scored the presence of parenchymal (opacities ≤2 cm, opacities >2 cm, and subtle interstitial), mediastinal, and pleural abnormalities on a five-point confidence scale. With CT as the reference standard, observer performance tests were carried out by using receiver operating characteristic (ROC) analysis. RESULTS: Analysis of averaged observer performance showed 2K and 4K images were equally effective in detection of all three groups of abnormalities. In the detection of the three subtypes of parenchymal abnormalities, there were no significant differences in averaged performance between the 2K and 4K formats (area below ROC curve [Az] values: opacities ≤2 cm, 0.62 ± 0.056 [standard error] and 0.59 ± 0.045; opacities >2. cm, 0.86 ± .025 and 0.85 ± 0.030; subtle interstitial abnormalities, 0.73 ± 0.041 and 0.72 ± 0.041). Averaged performance in detection of mediastinal and pleural abnormalities was equivalent (Az values: mediastinal, 0.70 ± 0.046 and 0.73 ± 0.033; pleural, 0.85 ± 0.032 and 0.86 ± 0.033). CONCLUSION: Observer performance in detection of parenchymal, mediastinal, and pleural abnormalities was not significantly different on 2K and 4K storage phosphor chest radiographs.
• Nino-Murcia, M., Jeffrey, J., Beaulieu, C., Li, K., & Rubin, G. (2001). Multidetector CT of the pancreas and bile duct system: Value of curved planar reformations. American Journal of Roentgenology, 176(3). doi:10.2214/ajr.176.3.1760689
• Rubin, G. (2001). Techniques for performing multidetector-row computed tomographic angiography. Techniques in Vascular and Interventional Radiology, 4(1). doi:10.1053/tvir.2001.22966
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  The introduction of multidetector-row computed tomography (CT) scanners has substantially improved the quality and ease of performing CT angiography. CT angiography is a robust method of volumetric vascular imaging that offers benefits over conventional angiography. As CT angiography has become a mainstream examination in many radiology departments, a discussion of techniques toward optimizing CT angiography performed with multidetector-row CT scanners is important. Key principles for optimizing spiral CT acquisition are discussed, and an explanation of multidetector-row CT principles germane to peripheral vascular imaging is presented. A discussion of contrast medium administration strategies ensues, with attention toward injection protocol and bolus timing. An overview of 3-dimensional visualization techniques is subsequently presented, followed by some general rules for CT angiographic interpretation. The article concludes with anatomically directed protocol considerations for the carotid and intracranial circulation, thoracic aorta, pulmonary arteries, abdominal aortoiliac system, renal arteries, and lower extremity arterial inflow and run-off. Copyright © 2001 by W.B. Saunders Company.
• Rubin, G., Schmidt, A., Logan, L., & Sofilos, M. (2001). Multi-detector row CT angiography of lower extremity arterial inflow and runoff: Initial experience. Radiology, 221(1). doi:10.1148/radiol.2211001325
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  PURPOSE: To assess the patterns of lower extremity arterial inflow and runoff opacification with four-channel multi-detector row computed tomographic (CT) angiography in a cohort of patients with disease warranting imaging of the lower extremity arterial system. MATERIALS AND METHODS: Twenty-four patients with symptomatic lower extremity arterial occlusive or aneurysmal disease underwent imaging with fourchannel multi-detector row CT from the supraceliac abdominal aorta through the feet. Transverse sections were acquired with a 2.5-mm nominal detector width and pitch of 6.0 (3.2-mm effective section thickness) following intravenous injection of 174-185 mL of iodinated contrast medium (300 mg iodine per milliliter). In each patient, attenuation measurements were recorded in 16 arterial and 16 venous locations. In 18 patients, two radiologists assessed the detectability and stenosis degree of 21 arterial segments per patient relative to these features at conventional angiography. RESULTS: A mean scannning time of 66 seconds was required to cover a mean of 1,233 mm, resulting in a mean of 908 transverse reconstructions. All 504 arterial segments were depicted and analyzable. Mean arterial attenuation ranged from 253 HU in the midabdominal aorta to 357 HU in the popliteal artery and 253 HU in the dorsalis pedis or posterior tibial artery measured inferior to the tibiotalar joint. Maximum mean venous enhancement (99 HU) was observed in the saphenous vein at the ankle, with all other venous stations measuring less than 74 HU. CONCLUSION: The arteries of lower extremity inflow and runoff can be reliably depicted with minimal venous enhancement by using multi-detector row CT.
• Tillich, M., Bell, R., Paik, D., Fleischmann, D., Sofilos, M., Logan, L., & Rubin, G. (2001). Iliac arterial injuries after endovascular repair of abdominal aortic aneurysms: Correlation with iliac curvature and diameter. Radiology, 219(1). doi:10.1148/radiology.219.1.r01ap15129
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  PURPOSE: To determine the relationship between iliac arterial tortuosity and cross-sectional area and the occurrence of iliac arterial injuries following transfemoral delivery of endovascular prostheses for repair of abdominal aortic aneurysms. MATERIALS AND METHODS: Iliac arterial curvature values and orthogonal cross-sectional areas were determined from helical computed tomographic (CT) data acquired in 42 patients prior to transfemoral delivery of aortic stent-grafts. The curvature and luminal cross-sectional area orthogonal to the median centerline were quantified every millimeter along the median centerline of the iliac arteries. An indicator of global iliac tortuosity, the iliac tortuosity index, was defined as the sum of the curvature values for all points with a curvature of 0.3 cm-1 or greater, and cross-sectional area (CSA) was indexed for all points as the mean cross-sectional diameter (D̄ = 2√[CSA/π]). Following stent-graft deployment, helical CT data were analyzed for the presence of iliac arterial dissections independently by two reviewers. RESULTS: Eighteen dissections were detected in 16 patients. The iliac tortuosity index was significantly larger in iliac arteries with dissections (35.5 ± 20.8 [mean ± SD]) when compared with both nondissected contralateral iliac arteries in the same patients (26.1 ± 21.0, P = .001) and iliac arteries in patients without any iliac arterial injury (20 ± 9, P = .009). The tortuosity index was higher ipsilateral to the primary component delivery in 10 of 11 iliac dissections that developed along the primary component delivery route. CONCLUSION: A high degree of iliac arterial tortuosity appears to impart greater risk for the development of iliac arterial injuries in patients undergoing transfemoral delivery of endovascular devices.
• Tillich, M., Hill, B., Paik, D., Petz, K., Napel, S., Zarins, C., & Rubin, G. (2001). Prediction of aortoiliac stent-graft length: Comparison of measurement methods. Radiology, 220(2). doi:10.1148/radiology.220.2.r01au21475
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  PURPOSE: To determine the accuracy of helical computed tomography (CT), projectional angiography derived from CT angiography, and intravascular ultra-sonographic withdrawal (IUW) length measurements for predicting appropriate aortoiliac stent-graft length. MATERIALS AND METHODS: Helical CT data from 33 patients were analyzed before and after endovascular repair of abdominal aortic aneurysm (Aneuryx graft, n = 31; Excluder graft, n = 2). The aortoiliac length of the median luminal centerline (MLC) and the shortest path (SP) that remained at least one common lilac arterial radius away from the vessel wall were calculated. Conventional angiographic measurements were simulated from CT data as the length of the three-dimensional MLC projected onto four standard viewing planes. These predeployment lengths and IUW length, available in 24 patients, were compared with the aortoiliac arterial length after stent-graft deployment. RESULTS: The mean error values of SP, MLC, the maximum projected MLC, and IUW were -2.1 mm ±4.6 (SD) (P = .013), 9.8 mm ± 6.8 (P < .001), -5.2 mm± 7.8 (P < .001), and -14.1 mm ± 9.3 (P < .001), respectively. The preprocedural prediction of the postprocedural aortoiliac length with the SP was significantly more accurate than that with the MLC (P < .001), maximum projected MLC (P < .001), and IUW (P < .001). CONCLUSION: The shortest aortoiliac path length maintaining at least one radius distance from the vessel wall most accurately enabled stent-graft length prediction for 31 AneuRx and two Excluder stent-grafts.
• Wolf, Y., Tillich, M., Lee, W., Rubin, G., Fogarty, T., & Zarins, C. (2001). Impact of aortoiliac tortuosity on endovascular repair of abdominal aortic aneurysms: Evaluation of 3D computer-based assessment. Journal of Vascular Surgery, 34(4). doi:10.1067/mva.2001.118586
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  Objective: The purpose of this study was to examine the effect of aortoiliac tortuosity, as assessed by observers and 3-dimensional (3D) computer-based methods, on the conduct and outcome of endovascular repair of abdominal aortic aneurysms. Methods: Infrarenal aortoiliac tortuosity was measured in 75 patients (mean follow-up, 14.8 ± 10.4 months) who underwent endovascular repair of abdominal aortic aneurysms by using the following four methods: (1) grading by 2 experienced observers; (2) tortuosity index measured as the inverse radius of curvature (cm-1) at 1-mm intervals along the median luminal centerline (MLC) on 3D reconstructions of computed tomography (CT) angiograms and was calculated as the sum of values greater than 0.3 cm-1; (3) MLC-straight line length ratio from renal to hypogastric arteries; (4) manual measurement of angles at points of angulation on anteroposterior and lateral projections of 3D CT reconstructions. In evaluating association between these measures, correlation between human observers was accepted as the gold standard. Results: For rating of overall aortoiliac tortuosity, interobserver correlation (r = 0.67) was comparable with correlation of observers with tortuosity index (r = 0.67 and 0.56), whereas correlations of each observer with MLC-straight line ratio (r = 0.50 and 0.56) and cumulative angulation (r = 0.44 and 0.44) were significant but weaker. For determining the relative tortuosity of right and left aortoiliac access, agreement between observers and tortuosity index (54% and 58%; P < .05; κ, 0.33 and 0.38) was not as good as between observers (68%; P
• Armerding, M., Rubin, G., Beaulieu, C., Slonim, S., Olcott, E., Samuels, S., Jorgensen, M., Semba, C., Jeffrey, R., & Dake, M. (2000). Aortic aneurysmal disease: Assessment of stent-graft treatment - CT versus conventional angiography. Radiology, 215(1). doi:10.1148/radiology.215.1.r00ap28138
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  PURPOSE: To compare computed tomographic (CT) angiography and conventional angiography for determining the success of endoluminal stent- graft treatment of aortic aneurysms. MATERIALS AND METHODS: Forty patients underwent conventional angiography and CT angiography following treatment of aortoiliac aneurysms with endoluminal stent-grafts. Six additional sets of conventional angiographic-CT angiographic examinations were performed in five patients after placement of additional stent-grafts or coil embolization to treat perigraft leakage. Three faculty CT radiologists who were blinded to patient clinical data and outcome independently interpreted the CT angiograms, and three faculty angiographers, who were not involved in the stent-graft deployment, interpreted the conventional angiograms. Images were assessed for the presence of postdeployment complications. A reference standard was developed by experienced radiologists using all available images and clinical data. Sensitivities, specificities, and κ values were calculated. RESULTS: Perigraft leakage was the most commonly identified complication. Twenty perigraft leaks were detected in the results of 46 examinations. Sensitivities and specificities for detecting perigraft leakage were 63% and 77% for conventional angiography and 92% and 90% for CT angiography, respectively. The κ value was 0.41 for conventional angiography and 0.81 for CT angiography. CONCLUSION: CT angiography is the preferred method for establishing the presence of perigraft leakage following treatment of aortoiliac aneurysms with stent-grafts.
• Cline, H., Coulam, C., Yavuz, M., Rubin, G., Edic, P., Pan, T., Shen, Y., Avila, R., Turek, M., Iatrou, M., Loree, A., Ishaque, N., & Senzig, R. (2000). Coronary artery angiography using multislice computed tomography images. Circulation, 102(13). doi:10.1161/01.cir.102.13.1589
• Fleischmann, D., Rubin, G., Bankier, A., & Hittmair, K. (2000). Improved uniformity of aortic enhancement with customized contrast medium injection protocols at CT angiography. Radiology, 214(2). doi:10.1148/radiology.214.2.r00fe18363
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  PURPOSE: To compare the uniformity of aortoiliac opacification obtained from uniphasic contrast medium injections versus individualized biphasic injections at computed tomographic (CT) angiography. MATERIALS AND METHODS: Thirty-two patients with an abdominal aortic aneurysm underwent CT angiography. In 16 patients (group 1), 120 mL of contrast material was administered at a flow rate of 4 mL/sec. In the other 16 patients (group 2), biphasic injection protocols were computed by using mathematic deconvolution of each patient's time-attenuation response to a standardized test injection. Attenuation uniformity was quantified as the 'plateau deviation' of enhancement values, which were calculated as the SD of the time-contiguous attenuation values observed during the 30-second scanning period. RESULTS: Group 2 patients received between 77 and 165 mL (mean, 115 mL) of contrast medium. Initial flow rates ranged from 4.1 to 10.0 mL/sec (mean, 6.8 mL/sec) for the first 4-6 seconds; continuing flow rates ranged from 2.0 to 4.8 mL/sec (mean, 3.1 mL/sec) for the remaining 24-26 seconds. The plateau deviation was significantly smaller in group 2 patients (19 HU) versus group 1 patients (38 HU, P < .001). CONCLUSION: At CT angiography, tailored biphasic injections led to more uniform aortoiliac enhancement, compared with standard uniphasic injections of contrast medium.
• Fleischmann, D., Rubin, G., Paik, D., Yen, S., Hilfiker, P., Beaulieu, C., & Napel, S. (2000). Stair-step artifacts with single versus multiple detector-row helical CT. Radiology, 216(1). doi:10.1148/radiology.216.1.r00jn13185
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  PURPOSE: To compare the effects of acquisition parameters on the magnitude and appearance of artifacts between single and multiple detector- row helical computed tomography (CT). MATERIALS AND METHODS: A cylindric (12.7 x 305.0-mm) acrylic rod inclined 45°relative to the z axis was scanned at the isocenter and 100 mm from the isocenter with single detector- row (single-channel) helical CT (beam width, 1-10 mm; pitch, 1.0, 2.0, or 3.0) and multiple detector-row (four-channel) helical CT (detector width, 1.25, 2.5, 3.75, and 5 mm; pitch, 0.75 or 1.5). The SD of radius measurements along the rod (SD(r)) was used to quantify artifacts in all 72 data sets and to analyze their frequency patterns. Volume-rendered images of the data sets were ranked by six independent and blinded readers; findings were correlated with acquisition parameters and SD(r) measurements. RESULTS: SD(r) was smaller in four- than in single-channel helical CT for any given table increment (TI). In single-channel helical CT, SD(r) increased linearly with beam width and geometrically with pitch. In four-channel helical CT, SD(r) measurements were directly proportional to the TI, regardless of the detector width and pitch combination used. Off-center object position on average increased SD(r) by a factor of 1.6 for single-channel helical CT and by a factor of 2.0 for four-channel helical CT. Subjective rankings of image quality correlated excellently with SD(r) (Spearman r = 0.94, P < .001). CONCLUSION: Artifacts are quantitatively and subjectively smaller with four- compared with single-channel helical CT for any given TI.
• Funabashi, N., & Rubin, G. (2000). Qualitative blood flow differentiation - Depiction of a left to right cardiac shunt across a ventricular septal defect using electron-beam computed tomography. Japanese Circulation Journal, 64(11). doi:10.1253/jcj.64.901
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  Three-dimensional imaging using electron-beam computed tomography (EBCT) has been used to assess static anatomical information in heart disease. With volume rendering, differences in objects can be distinguished through selection of the shape of opacity and color curves for CT values. If there is a difference between the CT values for arterial and venous blood, differences in opacity and color between them can be set. In a newborn baby with a left to right cardiac shunt across the ventricular septal defect (VSD), EBCT could depict arterial blood crossing the VSD into the right ventricle.
• Rubin, G. (2000). Alternative Visualization and Analysis of Volumetric Data. Computer Aided Surgery, 5(2). doi:10.3109/10929080009148883
• Rubin, G. (2000). Data explosion: The challenge of multidetector-row CT. European Journal of Radiology, 36(2). doi:10.1016/s0720-048x(00)00270-9
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  The development of multi detector-row CT has brought many exciting advancements to clinical CT scanning. While multi detector-row CT offers unparalleled speed of acquisition, spatial resolution, and anatomic coverage, a challenge presented by these advantages is the substantial increase on the number of reconstructed cross-sections that are rapidly created and in need of analysis. This manuscript discusses currently available alternative visualization techniques for the assessment of volumetric data acquired with multi detector-row CT. Although the current capabilities of 3-D workstations offer many possibilities for alternative analysis of MCDT data, substantial improvements both in automated processing, processing speed and user interface will be necessary to realize the vision of replacing the primary analysis of transverse reconstruction's with alternative analyses. The direction that some of these future developments might take are discussed. (C) 2000 Elsevier Science Ireland Ltd. The development of multi detector-row CT has brought many exciting advancements to clinical CT scanning. While multi detector-row CT offers unparalleled speed of acquisition, spatial resolution, and anatomic coverage, a challenge presented by these advantages is the substantial increase on the number of reconstructed cross-sections that are rapidly created and in need of analysis. This manuscript discusses currently available alternative visualization techniques for the assessment of volumetric data acquired with multi detector-row CT. Although the current capabilities of 3-D workstations offer many possibilities for alternative analysis of MCDT data, substantial improvements both in automated processing, processing speed and user interface will be necessary to realize the vision of replacing the primary analysis of transverse reconstruction's with alternative analyses. The direction that some of these future developments might take are discussed.
• Rubin, G., Armerding, M., Dake, M., & Napel, S. (2000). Cost identification of abdominal aortic aneurysm imaging by using time and motion analyses. Radiology, 215(1). doi:10.1148/radiology.215.1.r00ap4863
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  PURPOSE: To compare the costs of performing helical computed tomographic (CT) angiography with three-dimensional rendering versus intraarterial digital subtraction angiography (DSA) for preoperative imaging of abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: A single observer determined the variable direct costs of performing nine intraarterial DSA and 10 CT angiographic examinations in age- and general health-matched patients with AAA by using time and motion analyses. All personnel directly involved in the cases were tracked, and the involvement times were recorded to the nearest minute. All material items used during the procedures were recorded. The cost of labor was determined from personnel reimbursement data, and the cost of materials, from vendor pricing. The variable direct costs of laboratory tests and using the ambulatory treatment unit for postprocedural monitoring, as well as all fixed direct costs, were assessed from hospital accounting records. The total costs were determined for each procedure and compared by using the Student t test and calculating the CIs. RESULTS: The mean total direct cost of intraarterial DSA (± SD) was $1,052 ± 71, and that of CT angiography was $300 ± 30, which are significantly different (P < 4.1 x 10- 11). With 95% confidence, intraarterial DSA cost 3.2-3.7 times more than CT angiography for the assessment of AAA. CONCLUSION: Assuming equal diagnostic utility, and procedure-related morbidity, institutions may have substantial cost savings whenever CT angiography can replace intraarterial DSA for imaging AAAs.
• Rubin, G., Shiau, M., Leung, A., Kee, S., Logan, L., & Sofilos, M. (2000). Aorta and iliac arteries: Single versus multiple detector-row helical CT angiography. Radiology, 215(3). doi:10.1148/radiology.215.3.r00jn18670
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  PURPOSE: To compare single- versus four-channel helical computed tomographic (CT) aortography. MATERIALS AND METHODS: Forty-eight patients with aortic aneurysm or dissection underwent four- and one-channel CT angiography. Scan pairs covered the thoracic inlet to the diaphragm (n = 10) and supraceliac abdominal aorta (n = 19) or thoracic inlet (n = 19) to the femoral arterial bifurcations. For four-channel CT, nominal section thickness and pitch were 2.5 mm and 6.0, respectively, and for one-channel CT, 3.0 mm and 2.0 to the infrarenal aorta and 5.0 mm and 2.0 to the femoral arteries. Effective section thickness, scanning duration, scanning coverage, dose of iodinated contrast material, and mean aortoiliac attenuation were compared. Data were summarized as speed (coverage/duration), scanning efficiency (speed/section thickness), and contrast efficiency (mean aortic attenuation/dose of contrast material). RESULTS: At four- versus one-channel CT, CT angiography was 2.6 times faster, scanning efficiency was 4.1 times greater, contrast efficiency was 2.5 times greater, dose of contrast material was reduced (mean, 57%; 97 vs 232 mL) without a significant change in aortic enhancement, and sections were thinner (mean, 40‰; 3.2 vs 5.3 mm) despite a 59% shorter scanning duration (22 vs 56 seconds). CONCLUSION: Substantially reduced doses of contrast medium, shorter scanning durations, and narrower effective sections result with four- versus one-channel CT aortography. No advantages of one-channel CT aortography were demonstrated.
• Shiftman, S., Rubin, G., & Napel, S. (2000). Medical image segmentation using analysis of isolable-contour maps. IEEE Transactions on Medical Imaging, 19(11). doi:10.1109/42.896782
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  A common challenge for automated segmentation techniques is differentiation between images of close objects that have similar intensities, whose boundaries are often blurred due to partial-volume effects. We propose a novel approach to segmentation of two-dimensional images, which addresses this challenge. Our method, which we call intrinsic shape for segmentation (ISeg), analyzes isolabel-contour maps to identify coherent regions that correspond to major objects. ISeg generates an isolabel-contour map for an image by multilevel thresholding with a fine partition of the intensity range. ISeg detects object boundaries by comparing the shape of neighboring isolabel contours from the map. ISeg requires only little effort from users; it does not require construction of shape models of target objects. In a formal validation with computed-tomography angiography data, we showed that ISeg was more robust than conventional thresholding, and that ISeg's results were comparable to results of manual tracing.
• Wolf, Y., Hill, B., Rubin, G., Fogarty, T., & Zarins, C. (2000). Rate of change in abdominal aortic aneurysm diameter after endovascular repair. Journal of Vascular Surgery, 32(1). doi:10.1067/mva.2000.107754
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  Objective: Untreated abdominal aortic aneurysms (AAAs) enlarge at a mean rate of 3.9 mm/y with great individual variability. We sought to determine the effect of endovascular repair on the rate of change in aneurysm size. Methods: There were 110 patients who underwent endovascular AAA repair at Stanford University Medical Center and who were followed up for 1 to 30 months (mean, 10 months) with serial contrast-infused helical computed tomography (CT). Maximal aneurysm diameter was determined using two independent methods: (1) measured manually, from cross-sectional computed tomography (XSCT) angiograms and (2) calculated from quantitative three- dimensional computed tomography (3DCT) data as orthonormal diameter. Results: Maximal cross-sectional aneurysm diameter measured by hand (XSCT) and calculated as orthonormal values (3DCT) correlated closely (r = 0.915; P < .001). The XSCT-measured diameter was larger by 2.3 ± 3.75 mm (P < .001), and the 95% CI for SE of the bias was 1.85 to 2.75 mm. Preoperative aneurysm diameter (XSCT 59.1 ± 8.4 mm; 3DCT 58.1 ± 9.3 mm) did not differ significantly from the initial postoperative diameter. Considering all patients, XSCT diameter decreased at a rate of 0.34 ± 0.69 mm/mo, and 3DCT diameter decreased at a rate of 0.28 ± 0.79 mm/mo. Aneurysms in patients without endoleaks had a higher rate of decrease, an XSCT diameter by 0.50 ± 0.74 mm/mo, and 3DCT diameter by 0.46 ± 0.84 mm/mo. In these patients, mean absolute decrease in diameter at 6 months was 3.4 ± 4.5 mm (XSCT) and 3.3 ± 5.9 mm (3DCT) and at 12 months, 5.9 ± 5.7 mm (XSCT) and 5.4 ± 5.7 mm (3DCT). Aneurysms in patients with persistent endoleaks did not change in mean XSCT diameter, and 3DCT diameter increased by 0.12 ± 0.52 mm/mo (not significant). Aneurysm diameter remained within 4 mm of original size in 68% (3DCT) to 71% (XSCT) of patients. In one patient, aneurysm diameter increased (XSCT and 3DCT) more than 5 mm. Four patients who had a new onset endoleak had a much higher expansion rate than those with a chronic endoleak (P < .05). Conclusions: The rate of decrease in aneurysm size (annualized 3.4-4.1 mm/y) after endovascular repair of AAA approximates the reported expansion rate in untreated aneurysms. However, individual aneurysm behavior is unpredictable, and the presence of an endoleak is unreliable in predicting changes in diameter. New onset endoleaks are associated with an enlargement rate greater than that of untreated aneurysms.
• Wolf, Y., Johnson, B., Hill, B., Rubin, G., Fogarty, T., & Zarins, C. (2000). Duplex ultrasound scanning versus computed tomographic angiography for postoperative evaluation of endovascular abdominal aortic aneurysm repair. Journal of Vascular Surgery, 32(6). doi:10.1067/mva.2000.109210
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  Objective: The purpose of this study was to compare duplex ultrasound scanning and computed tomographic (CT) angiography for postoperative imaging and surveillance after endovascular repair of abdominal aortic aneurysm (AAA). Methods: One hundred consecutive patients with AAA underwent endovascular (Medtronic AneuRx, stent graft) aneurysm repair and were imaged with both CT angiography and duplex ultrasound scanning at regular intervals after the procedure. Each imaging modality was evaluated for technical adequacy and for documentation of aneurysm size, endoleak, and graft patency. In concurrent scan pairs, accuracy of duplex scanning was compared with CT. Results: A total of 268 CT scans and 214 duplex scans were obtained at intervals of 1 to 30 months after endovascular aneurysm repair (mean follow-up interval, 9 ± 7 months). All CT scans were technically adequate, and 198 (93%) of 214 duplex scans were technically adequate for the determination of aneurysm size, presence of endoleak, and graft patency. Concurrent (within 7 days of each other) scan pairs were obtained in 166 instances in 76 patients (1-6 per patient). The maximal transverse aneurysm sac diameter measured with both methods correlated closely (r = 0.93; P < .001) without a significant difference on paired analysis. In 92% of scans, measurements were within 5 mm of each other. Diagnosis of endoleak on both examinations correlated closely (P < .001), and compared with CT, duplex scanning had a sensitivity of 81%, a specificity of 95%, a positive predictive value of 94%, and a negative predictive value of 90%. Discordant results occurred in 8% of examinations, and in none of these was rite endoleak dose to the attachment sites or associated with aneurysm expansion. An endoleak was demonstrated on both tests in all eight patients who had an endoleak judged severe enough to warrant arteriography. Graft patency was documented in each instance, without discrepancy, with both modalities. Conclusions: High-quality duplex ultrasound scanning is comparable to CT angiography for the assessment of aneurysm size, endoleak, and graft patency after endovascular exclusion of AAA.
• Wolf, Y., Zarins, C., Rubin, G., & Fogarty, T. (2000). Concomitant endovascular repair of descending thoracic and abdominal aortic aneurysm.. Circulation, 102(6). doi:10.1161/01.cir.102.6.e36
• Zarins, C., Wolf, Y., Rubin, G., & Fogarty, T. (2000). Concomitant open surgical repair of an abdominal aortic aneurysm and endovascular repair of a thoracic aortic aneurysm. Journal of the American College of Surgeons, 190(6). doi:10.1016/s1072-7515(00)00303-3
• Hines, J., Katz, D., Goffner, L., & Rubin, G. (1999). Fat collection related to the intrahepatic inferior vena cava on CT. American Journal of Roentgenology, 172(2). doi:10.2214/ajr.172.2.9930793
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  OBJECTIVE. The purpose of our study is to describe the CT findings of fat collections related to the intrahepatic inferior vena cava and to review the literature about this benign incidental finding. CONCLUSION. Focal collections of fat related to the inferior vena cava are benign incidental findings located exclusively at the level of the liver. The fat collections are always adjacent to the medial wall of the inferior vena cava; appear to be extraluminal in origin and may, in fact, be entirely extraluminal; and are uncommon findings that are usually of no clinical significance.
• Katz, D., Jorgensen, M., & Rubin, G. (1999). Detection and follow-up of important extra-arterial lesions with helical CT angiography. Clinical Radiology, 54(5). doi:10.1016/s0009-9260(99)90557-3
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  AIM: To determine the prevalence and significance of extra-arterial findings detected prospectively on helical computed tomographic angiography (CTA). SUBJECTS AND METHODS: The official reports of 802 consecutive CTAs performed over a 4.5-year period on 624 patients and the reports of all radiographic follow-up studies were reviewed for identification of important extra-arterial findings. Medical records and imaging studies of all patients with previously unknown extra-arterial findings on CTA were reviewed to assess follow-up. In cases where follow-up was not indicated in the medical record, referring physicians were contacted directly. RESULTS: Important, previously unknown, extra-arterial findings were detected on 35 CTAs (4.4% of all CTAs, 5.6% of all patients), with 33 of 35 detected prospectively. Six lesions were consistent with and/or proven to be malignant. Important non-tumoural lesions were discovered on nine CTAs. Of 13 lesions with imaging features that were suspicious for malignancy. Five of these lesions proved to be benign, but radiographic and/or clinical follow-up was not obtained or could not be documented in eight patients. CONCLUSION: With the increasing use of CTA as a replacement for conventional angiography, careful attention should be paid to the visualized extra-arterial structures. Extra-vascular findings that are believed to be significant, may not be adequately followed-up by referring vascular specialists.
• Pitlick, P., Anthony, C., Moore, P., Shifrin, R., & Rubin, G. (1999). Three-dimensional visualization of recurrent coarctation of the aorta by electron-beam tomography and MRI. Circulation, 99(23). doi:10.1161/01.cir.99.23.3086
• Yen, S., Rubin, G., & Napel, S. (1999). Spatially varying longitudinal aliasing and resolution in spiral computed tomography. Medical Physics, 26(12). doi:10.1118/1.598801
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  Spiral computed tomography (CT) has revolutionized conventional CT as a truly three-dimensional imaging modality. A number of studies aimed at evaluating the longitudinal resolution in spiral CT have been presented, but the spatially varying nature of the longitudinal resolution in spiral CT has been largely left undiscussed. In this paper, we investigate the longitudinal resolution in spiral CT as affected by the spatially varying longitudinal aliasing. We propose the treatment of aliasing as a signal dependent, additive noise, and define a new image quality parameter, the contrast-to- aliased-noise ratio (CN(a)R), that relates to possible image degradation or loss of resolution caused by aliasing. We performed CT simulations and actual phantom scans using a resolution phantom consisting of sequences of spherical beads of different diameters, extending along the longitudinal axis. Our results show that the off-isocenter longitudinal resolution differs significantly from the longitudinal resolution at the isocenter and that the CN(a)R decreases with distance from the isocenter, and is a function of pitch and the helical interpolation algorithm used. The longitudinal resolution was observed to worsen with decreasing CN(a)R. We conclude that the longitudinal resolution in spiral CT is spatially varying, and can be characterized by the CN(a)R measured at the transaxial location of interest.
• Yen, S., Yan, C., Rubin, G., & Napel, S. (1999). Longitudinal sampling and aliasing in spiral CT. IEEE Transactions on Medical Imaging, 18(1). doi:10.1109/42.750254
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  Although analyses of in-plane aliasing have been done for conventional computed tomography (CT) images, longitudinal aliasing in spiral CT has not been properly investigated. We propose a mathematical model of the three-dimensional (3-D) sampling scheme in spiral CT and analyze its effects on longitudinal aliasing. We investigated longitudinal aliasing as a function of the helical-interpolation algorithm, pitch, and reconstruction interval using CT simulations and actual phantom scans. Our model predicts, and we verified, that for a radially uniform object at the isocenter, the spiral sampling scheme results in spatially varying cancellation of the aliased spectral islands which, in turn, results in spatially varying longitudinal aliasing. The aliasing is minimal at the scanner isocenter, but worsens with distance from it and rapidly becomes significant. Our results agree with published results observed at the isocenter of the scanner and further provide new insight into the aliasing conditions at off-isocenter locations with respect to the pitch, interpolation algorithm, and reconstruction interval. We conclude that longitudinal aliasing at off-isocenter locations can be significant, and that its magnitude and effects cannot be predicted by measurements made only at the scanner isocenter. © 1999 IEEE.
• Beaulieu, C., Napel, S., Daniel, B., Ch'en, I., Rubin, G., Johnstone, I., & Jeffrey, R. (1998). Detection of colonic polyps in a phantom model: Implications for virtual colonoscopy data acquisition. Journal of Computer Assisted Tomography, 22(4). doi:10.1097/00004728-199807000-00028
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  Purpose: Virtual colonoscopy is a new method of colon examination in which computer-aided 3D visualization of spiral CT simulates fiberoptic colonoscopy. We used a colon phantom containing various-sized spheres to determine the influence of CT acquisition parameters on lesion detectability and sizing. Method: Spherical plastic beads with diameters of 2.5, 4, 6, 8, and 10 mm were randomly attached to the inner wall of segments of plastic tubing. Groups of three sealed tubes were scanned at 3/1, 3/2, 5/1, and 5/2 collimation (mm)/pitch settings in orientations perpendicular and parallel to the scanner gantry. For each acquisition, image sets were reconstructed at intervals from 0.5 to 5.0 mm. Two blinded reviewers assessed transverse cross-sections of the phantoms for bead detection, using source CT images for images for acquisitions obtained with the tubes oriented perpendicular to the gantry and using orthogonal reformatted images for scans oriented parallel to the gantry. Results: Detection of beads of ≤4 mm was 100% for both tube orientations and for all collimator/pitch settings and reconstruction intervals. For the 2.5 mm beads, detection decreased to 78-94% for 5 mm collimation/pitch 2 scans when the phantom sections were oriented parallel to the gantry (p = 0.01). Apparent elongation of beads in the slice direction occurred as the collimation and pitch increased. The majority of the elongation (~75%) was attributable to changing the collimator from 3 to 5 mm, with the remainder of the elongation due to doubling the pitch from 1 to 2. Conclusion: CT scanning at 5 mm collimation and up to pitch 2 is adequate for detection of high contrast lesions as small as 4 mm in this model. However, lesion size and geometry are less accurately depicted than at narrower collimation and lower pitch settings.
• Gosselin, M., Rubin, G., Leung, A., Huang, J., & Rizk, N. (1998). Unsuspected pulmonary embolism: Prospective detection on routine helical CT scans. Radiology, 208(1). doi:10.1148/radiology.208.1.9646815
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  PURPOSE: To determine the prevalence of unsuspected pulmonary embolism (PE) on routine thoracic helical computed tomographic (CT) scans and to quantify the improvement in PE detection by using a cine-paging mode on a workstation instead of hard-copy review. MATERIALS AND METHODS: Seven hundred eighty-five patients referred for routine contrast medium-enhanced thoracic CT within 9 months were prospectively recruited. Helical CT was performed. Studies were prospectively interpreted by four radiologists. Two radiologists performed routine, undirected, hard-copy consensus review for official interpretation; two of three thoracic radiologists independently performed a dedicated workstation-based search for PE. The presence of PE involving the main, lobar, or segmental pulmonary arteries was assigned a score of 1-5 (1 = definitely negative, 5 = definitely positive) by each independent reviewer. Patients with a score of 4 or 5 underwent lower-extremity ultrasound, ventilation-perfusion scintigraphy, or both, followed by pulmonary CT angiography if the findings were still equivocal. RESULTS: Twelve (1.5%) of the 785 patients had unsuspected PE, with an inpatient prevalence of 5% (eight of 160) and an outpatient prevalence of 0.6% (four of 625). Of the 12 patients with unsuspectd PE, 10 (83%) had cancer. Of the 81 inpatients with cancer, seven (9%) had unsuspected PE. A dedicated workstation-based search resulted in detection of PE in three more patients (25%) than did hard-copy interpretation. CONCLUSION: The prevalence of unsuspectd PE was highest among inpatients with cancer. A directed, workstation-based search can improve the PE detection rate over that with hard-copy review.
• Lane, M., Katz, D., Shah, R., Rubin, G., & Jeffrey, R. (1998). Active arterial contrast extravasation on helical CT of the abdomen, pelvis, and chest. American Journal of Roentgenology, 171(3). doi:10.2214/ajr.171.3.9725295
• Paik, D., Beaulieu, C., Jeffrey, R., Rubin, G., & Napel, S. (1998). Automated flight path planning for virtual endoscopy. Medical Physics, 25(5). doi:10.1118/1.598244
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  In this paper, a novel technique for rapid and automatic computation of flight paths for guiding virtual endoscopic exploration of three-dimensional medical images is described. While manually planning flight paths is a tedious and time consuming task, our algorithm is automated and fast. Our method for positioning the virtual camera is based on the medial axis transform but is much more computationally efficient. By iteratively correcting a path toward the medial axis, the necessity of evaluating simple point criteria during morphological thinning is eliminated. The virtual camera is also oriented in a stable viewing direction, avoiding sudden twists and turns. We tested our algorithm on volumetric data sets of eight colons, one aorta and one bronchial tree. The algorithm computed the flight paths in several minutes per volume on an inexpensive workstation with minimal computation time added for multiple paths through branching structures (10%- 13% per extra path). The results of our algorithm are smooth, centralized paths that aid in the task of navigation in virtual endoscopic exploration of three-dimensional medical images.
• Rubin, G. (1998). Helical CT of potential living renal donors: toward a greater understanding.. Radiographics : a review publication of the Radiological Society of North America, Inc, 18(3). doi:10.1148/radiographics.18.3.9599385
• Rubin, G., Leung, A., Robertson, V., & Stark, P. (1998). Thoracic spiral CT: Influence of subsecond gantry rotation on image quality. Radiology, 208(3). doi:10.1148/radiology.208.3.9722858
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  PURPOSE: To determine if the lower milliampere second setting and shorter acquisition time of subsecond spiral computed tomography (CT) affects the image quality of thoracic CT scans. MATERIALS AND METHODS: In 92 consecutive outpatients referred for thoracic CT, spiral CT (120 kV, 292 mA) was performed with 1-second (n = 45) or 0.75-second (n = 47) scanning time. An equal percentage of patients (70%) in each group received intravenous contrast medium. At six mediastinal and six lung zones, degradation due to motion and noise, respectively, were graded independently on a four-point scale by three blinded radiologists. Statistically significant differences were determined with a two-tailed t test. RESULTS: Mediastinal image quality was significantly better on 0.75-second scans than on 1-second scans (P < .001). Regions with the greatest improvement in image quality were around the aortic root, cardiac ventricles, and aortic arch. Lung image quality was also better on 0.75-second scans than on 1-second scans (P = .04). On 0.75- and 1- second scans, respectively, motion-related artifacts were found to degrade image quality 6.2 and 8.7 times more than noise-related artifacts in the mediastinum and 2.6 and 3.9 times more in the lungs. CONCLUSION: Subsecond spiral CT is associated with improved clarity and diminished motion artifacts on mediastinal and pulmonary images when compared with 1-second spiral CT.
• Rubin, G., Paik, D., Johnston, P., & Napel, S. (1998). Measurement of the aorta and its branches with helical CT. Radiology, 206(3). doi:10.1148/radiology.206.3.9494508
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  Contiguous orthonormal arterial cross sections, segment lengths, and curvature were semiautomatically quantified from helical computed tomographic (CT) angiographic data in phantoms and two patients. Measurements of mean diameter and curvature correlated with reference values (r2 = .99), and mean fractional errors were 0.07 and 0.06 for mean diameter and curvature measurements, respectively. Volumetric measurement showed a potential to increase the accuracy, precision, and diagnostic utility of CT angiography.
• Brown, J., Lustrin, E., Lev, M., Taveras, J., Marks, M., & Rubin, G. (1997). CT angiography of the circle of Willis: Is spiral technology always necessary? [4] (multiple letters). American Journal of Neuroradiology, 18(9).
• Gilani, S., Norbash, A., Ringl, H., Rubin, G., Napel, S., & Terris, D. (1997). Virtual endoscopy of the paranasal sinuses using perspective volume rendered helical sinus computed tomography. Laryngoscope, 107(1). doi:10.1097/00005537-199701000-00008
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  Our goal was to use three-dimensional information obtained from helical computed tomographic (CT) data to explore and evaluate the nasal cavity, nasopharynx, and paranasal sinuses by simulated virtual endoscopy (VE). This was done by utilizing a new image reconstruction method known as perspective volume rendering (PVR). Thin-section helical CT of the nasal cavity, nasopharynx, and paranasal sinuses was performed on a conventional CT scanner. The data were transferred to a workstation to create views similar to those seen with endoscopy. Additional views not normally accessible by conventional endoscopy were generated. Key perspectives were selected, and a video 'flight' model was choreographed and synthesized through the nasal cavity and sinuses based on the CT data. VE allows evaluation of the nasal cavity, nasopharynx, and paranasal sinuses with appreciation of the relationships of these spatially complex structures. In addition, this technique allows structural visualization with unconventional angles, perspectives, and locations not conventionally accessible. Although biopsies, cultures, and lavages routinely done with endoscopy cannot be performed with VE, this technique holds promise for improving the diagnostic evaluation of the nasal cavity, the nasopharynx, and the paranasal sinuses. The unconventional visual perspectives and very low morbidity may complement many applications of simple diagnostic endoscopy.
• Gosselin, M., & Rubin, G. (1997). Altered Intravascular Contrast Material Flow Dynamics: Clues for Refining Thoracic CT Diagnosis. American Journal of Roentgenology, 169(6). doi:10.2214/ajr.169.6.9393173
• Li, K., Pelc, L., Napel, S., Goris, M., Lin, D., Song, C., Leung, A., Rubin, G., Hollett, M., & Harris, D. (1997). MRI of pulmonary embolism using Gd-DTPA-polyethylene glycol polymer enhanced 3D fast gradient echo technique in a canine model. Magnetic Resonance Imaging, 15(5). doi:10.1016/s0730-725x(97)00001-5
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  This study was to evaluate the accuracy of MR angiography (MRA) using a Gd-DTPA-polyethylene glycol polymer (Gd-DTPA-PEG) with a 3D fast gradient echo (3D fgre) technique in diagnosing pulmonary embolism in a canine model. Pulmonary emboli were created in six mongrel dogs (20-30 kg) by injecting tantalum oxide-duped autologous blood clots into the femoral veins via cutdowns. MRI was performed with a 1.5 T GE Signa imager using a 3D fgre sequence (11.9/2.3/15°) following intravenous injection of 0.06 mmol Gd/kg of Gd-DTPA-PEG. The dogs were euthanized and spiral CT of the lungs were then obtained on the deceased dogs. The MRI images were reviewed independently and receiver-operating-characteristic (ROC) curves were used for statistical analysis using spiral CT results as the gold standard. The pulmonary emboli were well visualized on spiral CT. Out of 108 pulmonary segments in the six dogs, 24 contained emboli >2 mm and 27 contained emboli ≤2 min. With unblinded review, MRI detected 79% of emboli >2 mm and only 48% of emboli ≤2 mm. The blinded review results were significantly worse. Gd-DTPA-PEG enhanced 3D fgre MRI is potentially able to demonstrate pulmonary embolism with fairly high degree of accuracy, but specialized training for the interpretations will be required.
• Norbash, A., Rubin, G., Napel, S., Gilani, S., Marks, M., & Steinberg, G. (1997). V. Virtual angioscopy with intravascular and extravascular computer generated videoangioscopy. Skull Base Surgery, 7(1).
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  PURPOSE: To videoscopically explore the outside and inside of 2 mm and larger blood vessels in the skull base and circle of Willis by simulated computer generated angioscopy (CGA) in normal and aneurysm populations as a diagnostic and preoperative tool. METHODS: Thin-section helical computerized tomographic angiography of the supracervical internal carotid artery was performed with spiral CT Angiography using a power injected intravenous contrast Material bolus. This data was transferred to an Infinite Reality workstation for extravascular perspective generation, and intravascular visualization. Key perspectives were selected, and a dynamic "flight" model was generated along juxtavascular and intravascular paths. The flight paths demonstrate specific anatomic regions of interest. RESULTS: Normal vasculature down to 2 millimeter vessel diameters is demonstrated from without and from within. With aneurysm samples, specific visualization of the native vessel, fundus, axilla, and aneurysm neck are internally and externally possible. CONCLUSIONS: Virtual videoangioscopic images hold promise for improving the diagnostic evaluation of vascular anatomy and pathology. These advantages may prove to be of considerable benefit in planning and followingup endovascular and conventional vascular surgical procedures.
• Rubin, G. (1997). Helical CT angiography of the thoracic aorta. Journal of Thoracic Imaging, 12(2). doi:10.1097/00005382-199704000-00011
• Rubin, G. (1997). Helical CT for the detection of acute pulmonary embolism: Experts debate. Journal of Thoracic Imaging, 12(2). doi:10.1097/00005382-199704000-00001
• Rubin, G., & Napel, S. (1997). Helical CT angiography of renal artery stenosis.. AJR. American journal of roentgenology, 168(4). doi:10.2214/ajr.168.4.9124125
• Chan, A., & Rubin, G. (1996). Multiple aortic aneurysms. Vascular Medicine, 1(3). doi:10.1177/1358863x9600100308
• Rubin, G., Beaulieu, C., Argiro, V., Ringl, H., Norbash, A., Feller, J., Dake, M., Jeffrey, R., & Napel, S. (1996). Perspective volume rendering of CT and MR images: Applications for endoscopic imaging. Radiology, 199(2). doi:10.1148/radiology.199.2.8668772
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  PURPOSE: To use perspective volume rendering (PVR) of computed tomographic (CT) and magnetic resonance (MR) imaging data sets to simulate endoscopic views of human organ systems. MATERIALS AND METHODS: Perspective views of helical CT and MR images were reconstructed from the data, and tissues were classified by assigning color and opacity based on their CT attenuation or MR signal intensity. 'Flight paths' were constructed through anatomic regions by defining key views along a spline path. Twelve movies of the thoracic aorta (n = 3), tracheobronchial tree (n = 4), colon (n = 3), paranasal sinuses (n = 1), and shoulder joint (n = 1) were generated to display images along the flight path. All abnormal results were confirmed at surgery. RESULTS: PVR fly-through enabled evaluation of the full range of tissue densities, signal intensities, and their three-dimensional spatial relationships. CONCLUSION: PVR is a novel way to present volumetric data and may enable noninvasive diagnostic endoscopy and provide an alternate method to analyze volumetric imaging data for primary diagnosis.
• Rubin, G., Lane, M., Bloch, D., Leung, A., & Stark, P. (1996). Optimization of thoracic spiral CT: Effects of iodinated contrast medium concentration. Radiology, 201(3). doi:10.1148/radiology.201.3.8939232
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  PURPOSE: To determine the effect of varying iodine concentration on arterial enhancement and perivenous artifact during thoracic spiral computed tomographic (CT) scanning. MATERIALS AND METHODS: One hundred thirty-eight outpatients received 15.0 g (n = 76) or 22.5 g (n = 62) of iodine (300 mg/mL iodine) while undergoing thoracic spiral CT. Patients received either undiluted contrast medium, 1:1 normal saline dilution, or 3:1 normal saline dilution. Contrast medium was injected at a flow rate determined to deliver the entire iodine dose within 40 seconds. Attenuation was measured within arteries and veins. Three blinded thoracic radiologists independently graded perivenous artifact and arterial enhancement. RESULTS: Perivenous artifacts were statistically significantly reduced with successive iodine dilution (P < .002). Arterial enhancement was statistically significantly better with 15.0 g of iodine diluted 1:1 when compared with the same iodine dose undiluted or diluted 3:1 (P < .01). Arterial enhancement achieved with 15.0 g of iodine diluted 1:1 was not statistically significantly lower than that achieved with 22.5 g of iodine diluted 1:1 (P > .31); however, venous artifact was greater with 22.5 g of iodine (P < .004). CONCLUSION: Reduced iodine concentration appears to diminish perivenous artifact and to result in improved arterial enhancement during thoracic spiral CT.
• Rubin, G., Napel, S., & Leung, A. (1996). Volumetric analysis of volumetric data: achieving a paradigm shift.. Radiology, 200(2). doi:10.1148/radiology.200.2.8685316
• Alfrey, E., Rubin, G., Kuo, P., Waskerwitz, J., Scandling, J., Mell, M., Brooke Jeffrey, R., Dafoe, D., Alfrey, E., Rubin, G., Kuo, P., Waskerwitz, J., Scandling, J., Mell, M., Brooke Jeffrey, R., & Dafoe, D. (1995). The use of spiral computed tomography in the evaluation of living donors for kidney transplantation. Transplantation, 59(4). doi:10.1097/00007890-199502270-00037
• Rubin, G. (1995). CT angiography earns role in thoracic aorta.. Diagnostic imaging, Suppl.
• Rubin, G. D., & Silverman, S. G. (1995). HELICAL (SPIRAL) CT OF THE RETROPERITONEUM. Radiologic Clinics of North America. doi:10.1016/s0033-8389(22)00630-3
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  Helical CT promises to improve imaging of the retroperitoneum through the elimination of respiratory misregistration and the minimization of partial volume averaging. The speed of acquisition enables the entire abdomen and pelvis to be imaged in less than 2 minutes with standard collimator widths. This is a distinct advantage in critically ill patients, particularly in the case of trauma. Selective intravenously administered contrast enhancement is made possible with helical CT. Rapid scanning allows imaging in an arterial, renal cortical, renal medullary, or delayed collecting system phase. This property of helical CT enables CT angiography to emerge as a powerful minimally invasive alternative to conventional arteriography for imaging the abdominal aorta and its branches. After 4 years of investigating the use of volumetric CT, the clinical settings described herein remain the only clear indications for using helical CT in the kidney and retroperitoneum. These studies took advantage of the single most important feature of helical CT—the elimination of respiratory misregistration. Two broad diagnostic advantages result: (1) the ability to search and characterize a region thoroughly, such as in the evaluation of a small renal mass, or to search for the needle-tip during an interventional procedure; and (2) the ability to create multiplanar and 3-D images that are of sufficient quality to be useful in clinical practice, such as in imaging the vasculature (CT angiogram), and in surgical planning.
• Rubin, G., & Napel, S. (1995). Increased scan pitch for vascular and thoracic spiral CT.. Radiology, 197(1). doi:10.1148/radiology.197.1.316-c
• Rubin, G., & Zarins, C. (1995). MR and spiral/helical CT imaging of lower extremity occlusive disease. Surgical Clinics of North America, 75(4). doi:10.1016/s0039-6109(16)46685-5
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  Magnetic resonance (MR) angiography and spiral CT angiography are promising new imaging modalities for evaluating patients with lower extremity arterial occlusive disease. Both techniques are less invasive than conventional angiography, and MR angiography has the additional advantages of not requiring iodinated contrast media or ionizing radiation. The basic principles of MR angiography and spiral CT angiography are reviewed with an emphasis on three-dimensional display techniques. This is followed by a discussion of their clinical applicability toward the diagnosis and treatment planning of lower extremity arterial occlusive disease.
• Rubin, G., Alfrey, E., Dake, M., Semba, C., Sommer, F., Kuo, P., Dafoe, D., Waskerwitz, J., Bloch, D., & Jeffrey, R. (1995). Assessment of living renal donors with spiral CT. Radiology, 195(2). doi:10.1148/radiology.195.2.7724766
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  PURPOSE: To determine whether spiral computed tomography (CT) can be used to evaluate potential living renal donors. MATERIALS AND METHODS: Twelve potential living renal donors underwent spiral CT and conventional arteriography. CT angiography was performed with 30-second spiral acquisition during injection of 150 mL of nonionic iodinated contrast material into an antecubital vein at 5 mL/sec. Five minutes after injection, a frontal abdominal scout projection was obtained to assess the renal collecting system. Results of blinded interpretations of axial CT angiograms, three- dimensional CT angiograms, and conventional arteriograms were correlated with intraoperative findings in 11 cases. RESULTS: Axial and three-dimensional CT angiography were 100% sensitive for identifying seven accessory renal arteries and 14% and 93% sensitive for identifying five prehilar renal artery branches. Renal venous anomalies were confirmed in three patients at surgery. Operative management changed in four of 11 patients who underwent donor nephrectomy. CONCLUSION: Spiral CT holds promise as a single examination for anatomic assessment of living renal donors.
• Sommer, F., Jeffrey, R., Rubin, G., Napel, S., Rimmer, S., Benford, J., & Harter, P. (1995). Detection of ureteral calculi in patients with suspected renal colic: Value of reformatted noncontrast helical CT. American Journal of Roentgenology, 165(3). doi:10.2214/ajr.165.3.7645461
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  OBJECTIVE. The purpose of this study was to determine the value of reformatted noncontrast helical CT in patients with suspected renal colic. We hoped to determine whether this technique might create images acceptable to both radiologists and clinicians and replace our current protocol of sonography and abdominal plain film. SUBJECTS AND METHODS. Thirty-four consecutive patients with signs and symptoms of renal colic were imaged with both noncontrast helical CT and a combination of plain film of the abdomen and renal sonography. Reformatting of the helical CT data was performed on a workstation to create a variety of reformatted displays. The correlative studies were interpreted by separate blinded observers. Clinical data, including the presence of hematuria and the documentation of stone passage or removal, were recorded. RESULTS. Findings on 18 CT examinations were interpreted as positive for the presence of ureteral calculi; 16 of these cases were determined to be true positives on the basis of later-documented passage of a calculus. Thirteen of the 16 cases proved to be positive were interpreted as positive for renal calculi using the combination of abdominal plain film and renal sonography. The most useful CT reformatting technique was curved planar reformatting of the ureters to determine whether a ureteral calculus was present. CONCLUSION. In this study, noncontrast helical CT was a rapid and accurate method for determining the presence of ureteral calculi causing renal colic. The reformatted views produced images similar in appearance to excretory urograms, aiding greatly in communicating with clinicians. Limitations on the technique include the time and equipment necessary for reformatting and the suboptimal quality of reformatted images when little retroperitoneal fat is present.
• Mell, M., Alfrey, E., Rubin, G., Scandling, J., Jeffrey, R., & Dafoe, D. (1994). Use of spiral computed tomography in the diagnosis of transplant renal artery stenosis. Transplantation, 57(5). doi:10.1097/00007890-199403150-00019
• Rubin, G. (1994). Three-dimensional helical CT angiography.. Radiographics : a review publication of the Radiological Society of North America, Inc, 14(4). doi:10.1148/radiographics.14.4.7938777
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  CT angiography can accurately depict vascular lesions in less time, with less patient morbidity, and at a lower cost than conventional angiography. Meticulous attention to scan technique is required for achieving diagnostic images. Regardless of the three-dimensional rendering techniques employed, a review of the original axial sections is always required to ensure the detection of any unsuspected parenchymal lesions present and to exclude inaccuracies in segmentation and three-dimensional rendering.
• Rubin, G., Herfkens, R., Pelc, N., Foo, T., Napel, S., Shimakawa, A., Steiner, R., & Bergin, C. (1994). Single breath-hold pulmonary magnetic resonance angiography: Optimization and comparison of three imaging strategies. Investigative Radiology, 29(8). doi:10.1097/00004424-199408000-00006
• Semba, C., Rubin, G., & Dake, M. (1994). Three-dimensional spiral CT angiography of the abdomen. Seminars in Ultrasound, CT, and MRI, 15(2). doi:10.1016/s0887-2171(05)80095-2
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  Spiral CT angiography is a technical innovation in vascular imaging that can produce spectacular three-dimensional reconstructions of the abdominal vessels and organs using modified CT scanning techniques. Rapid volume data acquisition allows contrast material to be imaged in the arterial or venous phase. CT reconstruction in cross-sections avoids superimposition of overlying structures. The combination of these features allows spiral CT angiography to produce extraordinary images of the abdominal vasculature and organs. This review outlines fundamental techniques in spiral CT angiography and summarizes our initial clinical experience at Stanford University Medical Center. © 1994 W. B. Saunders Company. All rights reserved.
• Napel, S., Rubin, G., & Jeffrey, R. (1993). Sts-mip: A new reconstruction technique for ct of the chest. Journal of Computer Assisted Tomography, 17(5). doi:10.1097/00004728-199309000-00036
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  The authors present sliding thin-slab maximum intensity projection (STS-MIP) as a technique for improved visualization of blood vessels and airways from rapidly acquired thin-section CT data. The STS-MIP reconstructions can be computed rapidly and without operator intervention directly from the transaxial sections. The resulting images retain the high contrast resolution of thin-section (1-3 mm) CT while providing vascular or airway visibility within a sequence of overlapping thin-slabs (3-10 mm). Examples are presented of pulmonary vessels and airways derived from spiral CT and of pulmonary vessels and coronary arteries derived from electron-beam CT. © 1993 Raven Press, Ltd., New York.
• Rhee, J., Rubin, G., Jeffrey, R., Dake, M., & Wittich, G. (1993). Septic thrombosis of the portal vein: Successful percutaneous drainage. Journal of Interventional Radiology, 8(2).
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  Septic thrombosis of the portal vein (STPV) is a rare complication of intra-abdominal infection. We report a case of successful percutaneous drainage in a patient with an infected portal venous clot who failed to respond to antibiotic therapy alone. To our knowledge, there has been only one previous report of an attempted percutaneous drainage in STPV. © 1993.
• Rubin, G., Dake, M., Napel, S., McDonnell, C., & Jeffrey, R. (1993). Three-dimensional spiral CT angiography of the abdomen: Initial clinical experience. Radiology, 186(1). doi:10.1148/radiology.186.1.8416556
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  Spiral computed tomography (CT) is a new technology that couples continuous tube rotation with continuous table feed. This allows compilation of a data set that has continuous anatomic information without the establishment of arbitrary boundaries at section interfaces as in conventional CT. The unique method of data collection of the spiral scanner has been combined with a dynamic intravenous contrast material bolus to image abdominal vasculature, specifically, the aorta, renal arteries, and splanchnic circulation. Through various techniques of image processing, including surface renderings and maximum-intensity projections, it is possible to obtain excellent anatomic detail of the aorta and its major branches. The authors applied this technique in 15 patients and reliably saw third-order aortic branches as well as third-order splenic-portal venous anatomic detail with remarkable clarity. Pathologic conditions detected include stenotic renal arteries, abdominal aortic dissection, abdominal aortic aneurysm, and celiac bypass graft occlusion.
• Rubin, G., Walker, P., Dake, M., Napel, S., Jeffrey, R., McDonnell, C., Mitchell, R., & Miller, D. (1993). Three-dimensional spiral computed tomographic angiography: An alternative imaging modality for the abdominal aorta and its branches. Journal of Vascular Surgery, 18(4). doi:10.1016/0741-5214(93)90075-w
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  Purpose: We sought to apply a new technique of computed tomographic angiography (CTA) to the preoperative and postoperative assessment of the abdominal aorta and its branches. Methods: After a peripheral intravenous contrast injection, the patient is continuously advanced through a spiral CT scanner, while maintaining a 30-second breath-hold. Thirty-five patients with abdominal aortic, renal, and visceral arterial disease have undergone CTA. Results: Diagnostic three-dimensional images were obtained in patients with aortic aneurysms (n = 9), aortic dissections (n = 4), and mesenteric artery stenoses (n = 4). The technique has also been used to assess vessels after operative reconstruction or endovascular intervention in 18 patients. These preliminary studies have correlated well with conventional arteriographic findings. In aneurysmal disease both the lumen and mural thrombus and associated renal artery stenoses are visualized. The true and false channels of aortic dissections and the perfusion source of the visceral vessels are clearly shown; patency of visceral and renal reconstruction or stent placement are confirmed. CTA is relatively noninvasive and can be completed in less time than conventional angiography with less radiation exposure. Conclusions: This initial experience suggests that CTA may be a valuable alternative to conventional arteriography in the evaluation of the aorta and its branches. © 1993.
• Napel, S., Marks, M. P., Marks, M., Rubin, G. D., Rubin, G., Dake, M. D., Dake, M., McDonnell, C. H., McDonnell, C., Song, S., Song, S., Enzmann, D. R., Enzmann, D., Jeffrey, R. B., & Jeffrey, R. (1992). CT angiography with spiral CT and maximum intensity projection. Radiology, 185(2). doi:10.1148/radiology.185.2.1410382
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  The authors describe a technique for obtaining angiographic images by means of spiral computed tomography (CT), preprocessing of reconstructed three-dimensional sections to suppress bone, and maximum intensity projection. The technique has some limitations, but preliminary results in 48 patients have shown excellent anatomic correlation with conventional angiography in studies of the abdomen, the circle of Willis in the brain, and the extracranial carotid arteries. With continued development and evaluation, CT angiography may prove useful as a screening tool or replacement for conventional angiography in some patients.
• Rubin, G., & Jeffrey, R. (1992). Graded compression sonography of abdominal neoplasms mimicking acute appendicitis. Gastrointestinal Radiology, 17(1). doi:10.1007/bf01888572
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  Over a 3-year period nine patients (mean age of 43 years) with acute abdominal pain and unsuspected abdominal neoplasms were referred for graded compression sonography to rule out appendicitis. Six of the nine patients had right lower quadrant neoplasms involving the cecum, terminal ileum, iliacus muscle, or iliac lymph nodes. However, in three patients neoplasm was noted outside the right iliac fossa involving the liver, right kidney, and upper abdominal mesentery. This study underscores the fact that in patients without sonographic evidence of acute appendicitis, a survey of the upper abdomen and right flank should routinely be performed in addition to scanning the right iliac fossa and pelvis. In patients more than 50 years of age neoplasm must also be kept in mind in the differential diagnosis of appendicitis. © 1992 Springer-Verlag New York Inc.
• Rubin, G., Napel, S., Dake, M., Walker, P., McDonnell, C., Marks, M., & Jeffrey, R. (1992). Spiral CT creates 3-D neuro, body angiograms.. Diagnostic imaging, 14(8).
• Rubin, G., Wittich, G., Walter, R., & Swanson, D. (1992). Percutaneous removal of small gallstones-in vitro comparison of baskets. Journal of Interventional Radiology, 7(1).
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  A variety of basket designs are available for percutaneous treatment of gallstones, though no systematic evaluation of their relative performance has been made. We evaluated the efficiency of two commercially available baskets and two prototype baskets to remove small stones from a simulated gallbladder in vitro. Best results were achieved with a prototype basket made of the nickle-titanium alloy Nitinol. © 1992.
• Rubin, G., Jeffrey, R., & Walter, J. (1991). Pancreatic microcystic adenoma presenting with acute hemoperitoneum: CT diagnosis. American Journal of Roentgenology, 156(4). doi:10.2214/ajr.156.4.2003439
• Rubin, G., Edwards, D., Reicher, M., Doemeny, J., & Carson, S. (1989). Diagnosis of pulmonary hemosiderosis by MR imaging. American Journal of Roentgenology, 152(3). doi:10.2214/ajr.152.3.573
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  We present a case of IPH in which MR imaging of pulmonary parenchymal hemosiderin showed a preferential T2 shortening by paramagnetic ferric iron similar to that occurring in evolving intracranial hematomas. This noninvasive diagnosis allowed initiation of therapy and stabilization of the patient's cardiorespiratory status before lung biopsy. We suggest that in patients whose radiographic and clinical presentations suggest IPH, the MR findings permit sufficient diagnostic confidence to defer invasive maneuvers until the patient is clinically stable.
• Rubin, G., van Sonnenberg, E., Casola, G., Withers, C., & Keightley, A. (1989). Appendiceal abscess with fistula to the fallopian tube: Demonstration and cure by percutaneous drainage. Journal of Interventional Radiology, 4(4).
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  A unique case of percutaneous drainage of a post-operative periappendiceal abscess that fistulised to the Fallopian tube is presented. Fistulisation may represent the anatomic mechanism by which fertility may be affected by periappendiceal abscesses. Mechanisms and data on possible effects on fertility are reviewed. The patient was cured and the fistula closed. © 1989.
• Pranzatelli, M., Rubin, G., & Robert Snodgrass, S. (1986). Serotonin-lesion Myoclonic syndromes. I. Neurochemical profile and S-1 receptor binding. Brain Research, 364(1). doi:10.1016/0006-8993(86)90987-x
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  This paper and the following one describe the effects of l-5-hydroxytryptophan (5-HTP) (after 3 intracisternal injections of 5,7-dihydroxytryptamine (DHT), fenfluramine (FF), p-chloroamphetamine (PCA) and drug combinations on (i) brain regional amine concentration (HPLC with LEC) and serotonin S-1 receptor binding; and (ii) 'serotonergic' behaviors in the same adult rats. Serotonin (5-HT) neurotoxins produced significantly different regional profiles of 5-HT depletion. Multiple DHT injections caused a 90-100% depletion of 5-HT concurrently in neocorex, hippocampus, striatum, septum/accumbens, pons, cerebellum, and cervical cord. Only PCA significantly depleted midbrain. Drug combinations with DHT resembled DHT alone rather than additive depletions, except for PCA + DHT, which produced a hybrid pattern of depletion. The S-1 binding assay, using cold 5-HT to displace [3H]5-HT, was performed with and without ascorbate, EDTA, CaC12, and pargyline. Without ascorbate, binding was specific, saturable, region-dependent, and non-linear with high (Kd 1-3 nM) and low affinity (10-20 nM) components but no coopeerativity (0.8

Proceedings Publications

• Geng, Y., Ren, Y., Hou, R., Han, S., Rubin, G., & Lo, J. (2019). 2.5D CNN model for detecting lung disease using weak supervision. In SPIE.
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  Our goal is to develop a 2.5D CNN model to detect multiple diseases in multiple organs in CT scans. In this study we investigated detection of 4 common diseases in the lungs, which are atelectasis, edema, pneumonia and nodule. Most existing algorithms for computer-aided diagnosis (CAD) of CT use 2D models for the axial slices. Our hypothesis is that by using information from all of the three views (coronal, sagittal and axial), we may achieve a better classification result, because some diseases may be more obvious from a different view or from the combination of multi-views. Our data consisted of 1089 CT scans, which contains 288 normal cases, 224 atelectasis cases, 156 edema cases, 225 pneumonia cases and 196 nodule cases. The cases were selected from approximately 5,000 chest CTs from Duke University Health System, and case-level labels were automatically extracted by simple rule-based filtering of the unstructured text from the radiology report. Each of these 5 categories excluded the others, which indicates that cases from each category will have either only one of the four diseases or no disease. To create 2.5D volume patches, we combined together three channels representing parallel slices in each of the three intersecting, orthogonal directions, resulting in sparsely sampled cubes of 20.2 x 20.2 x 20.2 mm. For each CT scan, the volume containing the lungs was identified with thresholding, and 30 patches were randomly sampled within that volume. Then three 3-channel images in each patch representing those 3 different directions were entered into 3 independent CNN paths separately, which were finally fused by a fully connected layer. We used a 4 fold cross-validation and evaluated our results using receiver operating characteristic (ROC) area under the curve (AUC). We achieved an average AUC of 0.891 for classifying normal vs. atelectasis disease, 0.940 for edema disease, 0.869 for pneumonia disease and 0.784 for nodule disease. We also implemented a train-validation-test process for each disease to evaluate the generalization of our model and again got comparable test results, 0.818 for atelectasis, 0.963 for edema, 0.878 for pneumonia and 0.784 for nodule. Despite the limitation of the small dataset scale, we demonstrated that we developed a generalizable 2.5D CNN model for detection of multiple lung diseases.

Presentations

• Rubin, G. D. (2022). Aortic Endografts: Issues for the Imager. Diagnostic Imaging Update. Jackson Hole, Wyoming: CME Science.