Unni Udayasankar

Interests

Teaching

Education of residents, fellows in the field of pediatric neuroradiologyDeveloping newer techniques of adult learning, moving away from conventional techniques of educationDeveloping a cloud-based learning platform to improve radiology educationUtilization of newer software tools to improve anatomic visualization of images to improve education of medical students and residents.

Research

MRE in Pediatric inflammatory bowel (IBD) disease, with special emphasis of newer imaging technique and sequences that help in differentiating active inflammatory disease from chronic fibrotic disease.Utility of imaging studies in children with acute abdominal pain in the emergency room: Emphasis on radiation dose reduction, increased use of non radiation based studies including ultrasound and MRI in acute abdominal conditions, specifically acute appendicitis. Assessment of image quality and dose reduction with multidetector CT in pediatric patients: Evaluation of careDose and care kV techniques.Effect of low dose studies in pediatric patients, low dose head CTs in children being followed up for various indications, extremity studies. Cerebral Arteriopathies in Pediatric Stroke: Imaging in assessment of vasculitidesVolumetric analysis of cerebral parenchyma in various diseases processes including Rassmussens encephalitis and severe hydrocephalus.Optimization of MR imaging protocols in Pediatric Imaging: Improvements in speed, efficiency and image quality. Reducing the need for sedation Advanced Imaging techniques for evaluation of fetal anomalies. Development of advanced hardware and software for magnetic resonance imaging of fetal diseases.

Courses

Scholarly Contributions

Chapters

• Udayasankar, U. K., Momin, Z., Small, W., & Small, W. C. (2008). 3-D Post-processing: Principles and Practical Applications. In MDCT. Springer, Milano. doi:10.1007/978-88-470-0832-8_8
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  Computed tomography (CT) has evolved considerably since its introduction more than three decades ago. In 1998, multi-detector row CT (MDCT) technology provided a key breakthrough in the field of radiology. Today, MDCT scanners enable the rapid acquisition of an exceptional number of thin sections during multiple phases of contrast enhancement. The increasing spatial and temporal resolutions have allowed major improvements to be made in differentiating and characterizing normal and abnormal structures and processes.

Journals/Publications

• Udayasankar, U. (2022). Combination therapy for unresectable primitive myxoid mesenchymal tumor of infancy: A story of cure. . Pediatr Blood Cancer, 69.
• Udayasankar, U. (2022). Imaging of Pediatric Spine and Spinal Cord Tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee/ASPNR White Paper. Pediatr Blood Cancer.
• Udayasankar, U. (2022). Spinal Epidural Lipomatosis Causing Lumbar Canal Stenosis: A Pictorial Essay on Radiological Grading and the Role of Bariatric Surgery Versus Laminectomy. Cureus. doi:doi:10.7759
• Mushtaq, R., Udayasankar, U., Desoky, S. M., & Gilbertson-Dahdal, D. (2021). "Performance of overnight on-call radiology residents in interpreting unenhanced abdominopelvic MRI studies performed for pediatric right lower quadrant abdominal pain". Pediatric Radiology.
• Udayasankar, U. (2022). ACR Appropriateness Criteria® Ataxia-Child. J Am Coll Radiol, 19.
• Udayasankar, U. (2022). Imaging of Right Lower Quadrant Pain in Children and Adolescents: AJR Expert Panel Narrative Review. AJR Am J Roentgenol.
• Udayasankar, U., Desoky, S. M., Kylathu, R., & Gilbertson-Dahdal, D. (2018). “Managing neonatal intestinal obstruction: clinical perspectives”. Research and Reports in Neonatology, 8:19-32.
• Udayasankar, U., Gilbertson-Dahdal, D., Arif Tiwari, H., Desoky, S. M., Shareef, F., Vedantham, S., Mushtaq, R., & Sawyer, D. M. (2021). Performance of overnight on-call radiology residents in interpreting unenhanced abdominopelvic MRI studies performed for pediatric right lower quadrant abdominal pain. Pediatric Radiology.
• Udayasankar, U., Gilbertson-Dahdal, D., Morello, F., Arif Tiwari, H., Desoky, S., & Warner, J. (2020). Non-enhanced MRI of the Abdomen and Pelvis in Comprehensive Evaluation of Acute Atraumatic Abdominal Pain in Children. American Journal of Radiology.
• , E. P., Trofimova, A., Milla, S. S., Ryan, M. E., Pruthi, S., Blount, J. P., Desai, N. K., Glenn, O. A., Islam, M. P., Kadom, N., Mirsky, D. M., Myseros, J. S., Partap, S., Radhakrishnan, R., Rose, E., Soares, B. P., Trout, A. T., Udayasankar, U. K., Whitehead, M. T., & Karmazyn, B. (2021). ACR Appropriateness Criteria® Seizures-Child. Journal of the American College of Radiology : JACR, 18(5S), S199-S211.
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  In children, seizures represent an extremely heterogeneous group of medical conditions ranging from benign cases, such as a simple febrile seizure, to life-threatening situations, such as status epilepticus. Underlying causes of seizures also represent a wide range of pathologies from idiopathic cases, usually genetic, to a variety of acute and chronic intracranial or systemic abnormalities. This document discusses appropriate utilization of neuroimaging tests in a child with seizures. The clinical scenarios in this document take into consideration different circumstances at the time of a child's presentation including the patient's age, precipitating event (if any), and clinical and electroencephalogram findings and include neonatal seizures, simple and complex febrile seizures, post-traumatic seizures, focal seizures, primary generalized seizures in a neurologically normal child, and generalized seizures in neurologically abnormal child. This practical approach aims to guide clinicians in clinical decision-making and to help identify efficient and appropriate imaging workup. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
• Artunduaga, M., Liu, C. A., Morin, C. E., Serai, S. D., Udayasankar, U., Greer, M. C., & Gee, M. S. (2021). Safety challenges related to the use of sedation and general anesthesia in pediatric patients undergoing magnetic resonance imaging examinations. Pediatric radiology, 51(5), 724-735.
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  The use of sedation and general anesthesia has facilitated the significant growth of MRI use among children over the last years. While sedation and general anesthesia are considered to be relatively safe, their use poses potential risks in the short term and in the long term. This manuscript reviews the reasons why MRI examinations require sedation and general anesthesia more commonly in the pediatric population, summarizes the safety profile of sedation and general anesthesia, and discusses an amalgam of strategies that can be implemented and can ultimately lead to the optimization of sedation and general anesthesia care within pediatric radiology departments.
• Desoky, S., & Udayasankar, U. K. (2021). Unenhanced MRI for Abdominal Pain in the Pediatric Emergency Department: Point-Safe and Comprehensive Assessment While Reducing Delay in Care. AJR. American journal of roentgenology, 216(4), 874-875.
• Sawyer, D. M., Mushtaq, R., Vedantham, S., Shareef, F., Desoky, S. M., Arif-Tiwari, H., Gilbertson-Dahdal, D. L., & Udayasankar, U. K. (2021). Performance of overnight on-call radiology residents in interpreting unenhanced abdominopelvic magnetic resonance imaging studies performed for pediatric right lower quadrant abdominal pain. Pediatric radiology, 51(8), 1378-1385.
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  Abdominopelvic magnetic resonance imaging (MRI) is increasingly being used to evaluate children with abdominal pain suspected of having acute appendicitis. At our institution, these examinations are preliminarily interpreted by radiology residents, especially when performed after hours.
• Sreedher, G., Ho, M. L., Smith, M., Udayasankar, U. K., Risacher, S., Rapalino, O., Greer, M. C., Doria, A. S., & Gee, M. S. (2021). Magnetic resonance imaging quality control, quality assurance and quality improvement. Pediatric radiology, 51(5), 698-708.
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  Quality in MR imaging is a comprehensive process that encompasses scanner performance, clinical processes for efficient scanning and reporting, as well as data-driven improvement involving measurement of key performance indicators. In this paper, the authors review this entire process. This article provides a framework for establishing a successful MR quality program. The collective experiences of the authors across a spectrum of pediatric hospitals is summarized here.
• Udayasankar, U., Pariury, H., Memmott, T., & Alfonso, J. H. (2021). Combination therapy for unresectable primitive myxoid mesenchymal tumor of infancy: A story of cure. Pediatric Blood & Cancer. doi:10.1002/pbc.29523
• , E. P., Ryan, M. E., Pruthi, S., Desai, N. K., Falcone, R. A., Glenn, O. A., Joseph, M. M., Maheshwari, M., Marin, J. R., Mazzola, C., Milla, S. S., Mirsky, D. M., Myseros, J. S., Niogi, S. N., Partap, S., Radhakrishnan, R., Robertson, R. L., Soares, B. P., Udayasankar, U. K., , Whitehead, M. T., et al. (2020). ACR Appropriateness Criteria® Head Trauma-Child. Journal of the American College of Radiology : JACR, 17(5S), S125-S137.
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  Head trauma is a frequent indication for cranial imaging in children. The majority of accidental pediatric head trauma is minor and sustained without intracranial injury. Well-validated pediatric-specific clinical decision guidelines should be used to identify very low-risk children who can safely forgo imaging. In those who require acute imaging, CT is considered the first-line imaging modality for suspected intracranial injury because of the short duration of the examination and its high sensitivity for acute hemorrhage. MRI can accurately detect traumatic complications, but often necessitates sedation in children, owing to the examination length and motion sensitivity, which limits rapid assessment. There is a paucity of literature regarding vascular injuries in pediatric blunt head trauma and imaging is typically guided by clinical suspicion. Advanced imaging techniques have the potential to identify changes that are not seen by standard imaging, but data are currently insufficient to support routine clinical use. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.
• Udayasankar, U. K., & Desoky, S. M. (2020). Non-Contrast MRI for Abdominal Pain in the Pediatric Emergency Department - Point: Safe and Comprehensive Assessment While Reducing Delay in Care. American Journal of Roentgenology.
• Udayasankar, U., & Desoky, S. (2020). Non-Contrast MRI for Abdominal Pain in the Pediatric Emergency Department. Point: Safe and Comprehensive Assessment While Reducing Delay in Care.. Am J Roentgenol..
• Udayasankar, U., Vedantham, S., Sawyer, D., & Mushtaq, R. (2020). Accuracy of Resident and Attending radiologist interpretations of abdominopelvic magnetic resonance imaging performed for pediatric acute appendicitis.. Pediatr Radiol, 50 (Suppl 1)., S58.
• Warner, J., Desoky, S., Tiwari, H. A., Morello, F., Gilbertson, D., & Udayasankar, U. (2020). Unenhanced MRI of the Abdomen and Pelvis in the Comprehensive Evaluation of Acute Atraumatic Abdominal Pain in Children. AJR. American journal of roentgenology, 215(5), 1218-1228.
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  The purpose of this study is to show the utility of rapid unenhanced MRI in the comprehensive assessment of acute atraumatic abdominal pain in children, including appendicitis and alternate diagnoses, and to review the MRI features of common acute abdominal and pelvic conditions in a large, single-institution cohort. Rapid unenhanced MRI is an excellent option for the initial, comprehensive evaluation of acute abdominal emergencies in pediatric patients because it can diagnose the full range of presenting abnormalities, including causes of abdominal pain warranting surgical and nonsurgical management.
• Warner, J., Warner, J., Desoky, S., Desoky, S., Arif Tiwari, H., Arif Tiwari, H., Morello, F., Morello, F., Gilbertson-Dahdal, D., Gilbertson-Dahdal, D., Udayasankar, U., & Udayasankar, U. (2020). Unenhanced MRI of the Abdomen and Pelvis in the Comprehensive Evaluation of Acute Atraumatic Abdominal Pain in Children. American Journal of Roentgenology.
• Choudhary, G., Udayasankar, U., Saade, C., Winegar, B., Maroun, G., & Chokr, J. (2019). A systematic approach in the diagnosis of paediatric skull lesions: what radiologists need to know. Polish journal of radiology, 84, e92-e111.
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  Paediatric skull lesions are commonly identified on imaging. They can be challenging to image, given their location and size, and often require several imaging modalities to narrow down the differential diagnosis. Accurate diagnosis of these lesions is paramount because the clinical therapy can vary tremendously. In this review, we provide a simple and systematic approach to clinical-radiological features of primary skull lesions. We highlight the imaging characteristics and differentiate pathologies based on imaging appearances. We also accentuate the role of cross-sectional imaging in lesion identification and management implications.
• K, A., S, I., Dheeraj, G., & Udayasankar, U. (2019). MR Brain Imaging in Assessment of Pediatric Head Trauma.. Radiol Open J., 3(1), 19-26.
• Mushtaq, R., Desoky, S. M., Morello, F., Gilbertson-Dahdal, D., Gopalakrishnan, G., Leetch, A., Vedantham, S., Kalb, B., Martin, D. R., & Udayasankar, U. K. (2019). First-Line Diagnostic Evaluation with MRI of Children Suspected of Having Acute Appendicitis. Radiology, 291(1), 170-177.
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  Background Advances in abdominal MRI have enabled rapid, free-breathing imaging without the need for intravenous or oral contrast material. The use of MRI as the primary imaging modality for suspected appendicitis has not been previously studied. Purpose To determine the diagnostic performance of MRI as the initial imaging modality in children suspected of having acute appendicitis. Materials and Methods The study included consecutive patients 18 years of age and younger presenting with acute abdominal pain at a tertiary care institution from January 2013 through June 2016 who subsequently underwent an unenhanced MRI examination as the primary diagnostic imaging modality. Electronic medical records and radiology reports were retrospectively evaluated for the feasibility and diagnostic performance of MRI, with surgical pathology and follow-up electronic records as reference standards. Statistical analyses were performed by using simple binomial proportions to quantify sensitivity, specificity, and accuracy, and exact 95% confidence intervals (CIs) were obtained. Results After exclusions, 402 patients (median age: 13 years; interquartile range [IQR], 9-15 years; 235 female patients; 167 male patients) were included. Sedation for MRI was required in 13 of 402 patients (3.2%; 95% CI: 1.7%, 5.5%). The appendix was visualized in 349 of 402 patients (86.8%; 95% CI: 83.1%, 90%); for the remaining patients, a diagnosis was provided on the basis of secondary signs of appendicitis. The sensitivity, specificity, and accuracy of MRI as the primary diagnostic imaging modality for the evaluation of acute appendicitis were 97.9% (95 of 97; 95% CI: 92.8%, 99.8%), 99% (302 of 305; 95% CI: 97.2%, 99.8%), and 98.8% (397 of 402; 97.1%, 99.6%), respectively. Among patients with negative findings for appendicitis at MRI, an alternate diagnosis was provided in 113 of 304 patients (37.2%; 95% CI: 31.7%, 42.9%). Conclusion When performed as the initial imaging modality in children suspected of having acute appendicitis, MRI examinations had high diagnostic performance for the diagnosis of acute appendicitis and in providing alternative diagnoses. © RSNA, 2019 See also the editorial by Dillman and Trout in this issue.
• Udayasankar, U., Udayasankar, U., Martin, D. R., Martin, D. R., Kalb, B. T., Kalb, B. T., Gopalakrishnan, G., Gopalakrishnan, G., Vedantham, S., Vedantham, S., Leetch, A. N., Leetch, A. N., Gilbertson-Dahdal, D., Gilbertson-Dahdal, D., Morello, F., Morello, F., Desoky, S. M., Desoky, S. M., Mushtaq, R., & Mushtaq, R. (2019). First-Line Diagnostic Evaluation of Children with Suspected Acute Appendicitis using MRI. Radiology, 291(1), 170-177. doi:10.1148/radiol.2019181959
• Friedman, E., Patiño, M. O., & Udayasankar, U. K. (2018). Imaging of Pediatric Salivary Glands. Neuroimaging clinics of North America, 28(2), 209-226.
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  Salivary gland diseases in children are uncommon, and the relative incidence of pathologies is different than in adults. This article presents a comprehensive review of congenital and acquired disorders that affect the major salivary glands in the pediatric population, highlighting the imaging findings that are important in defining the appropriate diagnosis or narrowing of the differential diagnosis.
• Gilbertson-Dahdal, D., Udayasankar, U., Kylat, R. I., & Desoky, S. M. (2018). Managing Neonatal Bowel Obstruction: Clinical Perspectives. Research and Reports in Neonatology, 8, 19-32. doi:10.2147/RRN.S125760
• Hershman, M., Carmody, R., & Udayasankar, U. K. (2018). Case 252: Acute Hyperammonemic Encephalopathy Resulting from Late-Onset Ornithine Transcarbamylase Deficiency. Radiology, 287(1), 353-359.
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  History A 19-year-old woman with no pertinent medical history was brought to the emergency department after being found unconscious on her bathroom floor by her roommate. In the preceding weeks, she had reported intractable nausea and vomiting, for which she had been taking ondansetron. No other medications had been prescribed. The day prior to presentation, she had contacted her mother and described increasing confusion. Glasgow coma scale score on arrival in the emergency department was 4. Intravenous naloxone was administered, without immediate response. Initial blood glucose level was 232 mg/dL (12.8 mmol/L) (normal range, 79-140 mg/dL [4.4- 7.7 mmol/L]), and other routine laboratory test results were normal. Urine toxicology results were negative. Cerebrospinal fluid evaluation revealed levels were within normal limits. Neurologic examination revealed dilated pupils, which showed a sluggish response to light, and left lower extremity rigidity with intermittent tremors. Initial unenhanced cranial computed tomographic (CT) findings were negative. Magnetic resonance (MR) imaging of the brain was performed. The patient's condition deteriorated, with increasing cerebral edema over the next week, and she was declared brain dead. Her liver was transplanted into an adult recipient, who subsequently developed cerebral edema and elevated plasma ammonia levels, resulting in death in the immediate postoperative period.
• Manjila, S., Bazil, T., Kay, M., Udayasankar, U. K., & Semaan, M. (2018). Jugular bulb and skull base pathologies: proposal for a novel classification system for jugular bulb positions and microsurgical implications. Neurosurgical focus, 45(1), E5.
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  OBJECTIVE There is no definitive or consensus classification system for the jugular bulb position that can be uniformly communicated between a radiologist, neurootologist, and neurosurgeon. A high-riding jugular bulb (HRJB) has been variably defined as a jugular bulb that rises to or above the level of the basal turn of the cochlea, within 2 mm of the internal auditory canal (IAC), or to the level of the superior tympanic annulus. Overall, there is a seeming lack of consensus, especially when MRI and/or CT are used for jugular bulb evaluation without a dedicated imaging study of the venous anatomy such as digital subtraction angiography or CT or MR venography. METHODS A PubMed analysis of "jugular bulb" comprised of 1264 relevant articles were selected and analyzed specifically for an HRJB. A novel classification system based on preliminary skull base imaging using CT is proposed by the authors for conveying the anatomical location of the jugular bulb. This new classification includes the following types: type 1, no bulb; type 2, below the inferior margin of the posterior semicircular canal (SCC), subclassified as type 2a (without dehiscence into the middle ear) or type 2b (with dehiscence into the middle ear); type 3, between the inferior margin of the posterior SCC and the inferior margin of the IAC, subclassified as type 3a (without dehiscence into the middle ear) and type 3b (with dehiscence into the middle ear); type 4, above the inferior margin of the IAC, subclassified as type 4a (without dehiscence into the IAC) and type 4b (with dehiscence into the IAC); and type 5, combination of dehiscences. Appropriate CT and MR images of the skull base were selected to validate the criteria and further demonstrated using 3D reconstruction of DICOM files. The microsurgical significance of the proposed classification is evaluated with reference to specific skull base/posterior fossa pathologies. RESULTS The authors validated the role of a novel classification of jugular bulb location that can help effective communication between providers treating skull base lesions. Effective utilization of the above grading system can help plan surgical procedures and anticipate complications. CONCLUSIONS The authors have proposed a novel anatomical/radiological classification system for jugular bulb location with respect to surgical implications. This classification can help surgeons in complication avoidance and management when addressing HRJBs.
• Manjila, S., Bazil, T., Thomas, M., Mani, S., Kay, M., & Udayasankar, U. (2018). A review of extraaxial developmental venous anomalies of the brain involving dural venous flow or sinuses: persistent embryonic sinuses, sinus pericranii, venous varices or aneurysmal malformations, and enlarged emissary veins. Neurosurgical focus, 45(1), E9.
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  This paper is a narrative review of extraaxial developmental venous anomalies (eDVAs) of the brain involving dural venous flow or sinuses: persistent embryonic sinuses, sinus pericranii, enlarged emissary veins, and venous varices or aneurysmal malformations. The article highlights the natural history, anatomy, embryology, imaging, clinical implications, and neurosurgical significance of these lesions, which the authors believe represent a continuum, with different entities characterized by distinct embryopathologic features. The indications and surgical management options are discussed for these individual intracranial pathologies with relevant illustrations, and a novel classification is proposed for persistent falcine sinus (PFS). The role of neurointervention and/or microsurgery in specific cases such as sinus pericranii and enlarged emissary veins of the skull is highlighted. A better understanding of the pathophysiology and developmental anatomy of these lesions can reduce treatment morbidity and mortality. Some patients, including those with vein of Galen malformations (VOGMs), can present with the added systemic morbidity of a high-output cardiac failure. Although VOGM is the most studied and classified of the above-mentioned eDVAs, the authors believe that grouping the former with the other venous anomalies/abnormalities listed above would enable the clinician to convey the exact morphophysiological configuration of these lesions, predict their natural history with respect to evolving venous hypertension or stroke, and extrapolate invaluable insights from VOGM treatment to the treatment of other eDVAs. In recent years, many of these symptomatic venous malformations have been treated with endovascular interventions, although these techniques are still being refined. The authors highlight the broad concept of eDVAs and hope that this work will serve as a basis for future studies investigating the role of evolving focal venous hypertension/global intracranial hypertension and possibilities of fetal surgical intervention in these cases.
• Warhadpande, D., Desoky, S. M., Park, E., & Udayasankar, U. (2018). Imaging of Knee Swelling in Children. Contemporary Diagnostic Radiology, 41(1), 1-7.
• Chaudhary, G., Chokr, J., & Udayasankar, U. (2017). Imaging of Atypical Brain Infections and Infection Mimics in Children. Journal of Pediatric Neurology, 15(5), 228-240.
• Desoky, S. M., Kylat, R. I., Udayasankar, U., & Gilbertson-Dahdal, D. (2017). Managing Neonatal Bowel Obstruction: Clinical Perspectives. Research and Reports in Neonatology, 8, 19-32. doi:10.2147/RRN.S125760
• Hershman, M., Carmody, R., & Udayasankar, U. K. (2017). Case 252. Radiology, 285(3), 1042-1044.
• Ho, M. L., Campeau, N. G., Ngo, T. D., Udayasankar, U. K., & Welker, K. M. (2017). Pediatric brain MRI part 1: basic techniques. Pediatric radiology, 47(5), 534-543.
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  Pediatric neuroimaging is a complex and specialized field that uses magnetic resonance (MR) imaging as the workhorse for diagnosis. Standard MR techniques used in adult neuroimaging are suboptimal for imaging in pediatrics because there are significant differences in the child's developing brain. These differences include size, myelination and sulcation. MR protocols need to be tailored to the specific indication and reviewed by the supervising radiologist in real time, and the specialized needs of this population require careful consideration of issues such as scan timing, sequence order, sedation, anesthesia and gadolinium administration. In part 1 of this review, we focus on basic protocol development and anatomical characterization. We provide multiple imaging examples optimized for evaluation of supratentorial and infratentorial brain, midline structures, head and neck, and intracranial vasculature.
• Ho, M. L., Campeau, N. G., Ngo, T. D., Udayasankar, U. K., & Welker, K. M. (2017). Pediatric brain MRI, Part 2: Advanced techniques. Pediatric radiology, 47(5), 544-555.
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  Pediatric neuroimaging is a complex and specialized field that uses magnetic resonance (MR) imaging as the workhorse for diagnosis. MR protocols should be tailored to the specific indication and reviewed by the supervising radiologist in real time. Targeted advanced imaging sequences can be added to provide information regarding tissue microstructure, perfusion, metabolism and function. In part 2 of this review, we highlight the utility of advanced imaging techniques for superior evaluation of pediatric neurologic disease. We focus on the following techniques, with clinical examples: phase-contrast imaging, perfusion-weighted imaging, vessel wall imaging, diffusion tensor imaging, task-based functional MRI and MR spectroscopy.
• Kara, S. A., Chaudhary, G., & Udayasankar, U. (2017). Imaging in Meningitis and Meningoencephalitis in Children.. Journal of Pediatric Neurology, 15(5), 221-227.
• Kara, S. A., Chaudhary, G., & Udayasankar, U. (2017). Infections of the Spine and Spinal Cord in Children.. Journal of Pediatric Neurology, 15(5), 241-250.
• Udayasankar, U. (2017). Magnetic resonance imaging of the brain and spine, 5th edition. Journal of magnetic resonance imaging : JMRI.
• Udayasankar, U. (2017). Pediatric Neuroradiology: Clinical Practice Essentials. Journal of Magnetic Resonance Imaging, 221.
• Winegar, B., & Udayasankar, U. (2017). Imaging of Pediatric Paranasal Sinus and Orbital Infections. Journal of Pediatric Neurology, 15(5), 251-262.
• Aziz, H. A., Plesec, T. P., Sabella, C., Udayasankar, U. K., & Singh, A. D. (2016). Cat Scratch Disease: Expanded Spectrum. Ocular oncology and pathology, 2(4), 246-250.
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  To expand the spectrum of ophthalmic manifestations in cat scratch disease.
• Grossniklaus, H. E., Magrath, G. N., Craven, C., Anninger, W. V., Aziz, H., Bessette, A., Burris, C. K., Cohen, V. M., Damento, G. M., Deepa, P. R., Eagle, R. C., Espana, E. M., Fisher, G. H., Fraga, L. A., Gauthier, A. C., Goto, H., Grantham, M., Hay, G., Ho, D. K., , Jacinto, F. A., et al. (2016). Contents Vol. 2, 2016. Ocular Oncology and Pathology, 2(4). doi:10.1159/000450845
• Hansra, H., & Udayasankar, U. (2016). Medical image of the week: Sarcoidosis. Southwest J Pulm Crit Care, 12(2), 62-3.
• He, L., Park, E., Vachhani, N., Vogelius, E., Thupili, C., & Udayasankar, U. (2016). Acute abdominal pain in children: usefulness of three-view abdominal radiographs in the emergency department. Emergency radiology, 23(5), 469-75.
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  Diagnostic imaging is often an integral component in the workup of a pediatric patient with acute abdominal pain. The purpose of this study was to compare the diagnostic value of a three-view acute abdominal series (AAS) with that of a single supine view (SSV) in children with acute abdominal pain. All subjects aged ≤18 years that underwent an emergency three-view AAS examination for acute abdominal pain at a single urban hospital system were included. Retrospective evaluation of radiological diagnosis, number of radiological images, further imaging, management, and clinical outcomes was performed. "Positive" AAS studies were compared with corresponding SSV images for direct comparison of diagnostic value. Standard nonparametric statistical evaluation was performed. Five hundred forty-one AAS studies were included in the study. Greater than three radiographs were acquired in 29 % (153/541) of the subjects. Two hundred ninety-nine out of 541 AAS studies included a technically adequate SSV of the abdomen and pelvis. Most AAS examinations were categorized as negative (n = 485; 90 %). Of the 56 examinations initially classified as positive, there was no significant statistical difference between diagnostic accuracy between the AAS and SSV on retrospective evaluation. For pediatric subjects with nontraumatic acute abdominal pain, the yield of conventional radiographic study is exceedingly low. If required, a technically adequate single supine anteroposterior (AP) view of the abdomen and pelvis is sufficient for initial radiographic evaluation while reducing unnecessary radiation exposure to the patient.
• Li, J., Udayasankar, U. K., Carew, J., & Small, W. C. (2016). CT-guided liver biopsy: correlation of procedure time and radiation dose with patient size, weight, and lesion volume and depth. Clinical imaging, 34(4), 263-8.
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  The purpose of this study was to retrospectively evaluate the effect of various factors, including overall patient size, weight, and individual lesion characteristics, on the radiation dose and procedure time required to successfully perform computed tomography (CT)-guided liver lesion biopsies.
• Li, J., Udayasankar, U. K., Tang, X., Carew, J., Toth, T. L., & Small, W. C. (2016). An optimal contrast dose indicator for the determination of hepatic enhancement in abdominal multidetector computed tomography: comparison of patient attenuation indicator with total body weight and body mass index. Journal of computer assisted tomography, 34(6), 874-8.
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  To evaluate a patient attenuation indicator (PAI) as compared with traditional patient-related factors of total body weight and body mass index (BMI) as a predictor of hepatic enhancement in contrast-enhanced abdominal multidetector computed tomography (MDCT).
• Petkovska, I., Duke, E., Martin, D. R., Irani, Z., Geffre, C. P., Cragun, J. M., Costello, J. R., Arif-Tiwari, H., Czeyda-Pommersheim, F., Udayasankar, U., & Kalb, B. (2016). MRI of ovarian torsion: Correlation of imaging features with the presence of perifollicular hemorrhage and ovarian viability. European journal of radiology, 85(11), 2064-2071.
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  The purpose of our study is to test for: (a) correlation between the presence of a perifollicular T2-hypointense rim on MRI with the presence of perifollicular hemorrhage on histology; and (b) correlation between this finding and diminished ovarian viability after intra-operative detorsion.
• Wang, Z. I., Krishnan, B., Shattuck, D. W., Leahy, R. M., Moosa, A. N., Wyllie, E., Burgess, R. C., Al-Sharif, N. B., Joshi, A. A., Alexopoulos, A. V., Mosher, J. C., Udayasankar, U., & Jones, S. E. (2016). Automated MRI Volumetric Analysis in Patients with Rasmussen Syndrome. AJNR. American journal of neuroradiology.
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  Rasmussen syndrome, also known as Rasmussen encephalitis, is typically associated with volume loss of the affected hemisphere of the brain. Our aim was to apply automated quantitative volumetric MR imaging analyses to patients diagnosed with Rasmussen encephalitis, to determine the predictive value of lobar volumetric measures and to assess regional atrophy differences as well as monitor disease progression by using these measures.
• Yazdani, M., Park, E., & Udayasankar, U. K. (2016). Postsurgical diaphragmatic herniation: A rare delayed complication of pediatric intraabdominal surgery.. Journal of pediatric surgery, 51(2), 333-5. doi:10.1016/j.jpedsurg.2015.11.019
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  Spontaneous diaphragmatic herniation as a delayed complication of intraabdominal surgery is an exceedingly rare event in children with few cases reported in the literature. Almost all reported cases are on the right side and followed liver transplantation surgery. We present two pediatric cases of spontaneous diaphragmatic herniation as complications of two different abdominal surgeries: pancreatic pseudocyst resection with splenectomy and liver transplantation.
• Hansra, H., & Udayasankar, U. (2016). Medical image of the week: Phytobezoar. Southwest J Pulm Crit Care, 12(1), 20-1.
• Kiczek, M., & Udayasankar, U. (2015). Page Kidney. The Journal of urology, 1109-10.
• Obusez, E. C., & Udayasankar, U. (2015). Autosomal recessive polycystic kidney disease with Caroli syndrome. The Journal of urology, 679-80.
• Thupili, C. R., Udayasankar, U., & Renapurkar, R. (2015). Bilateral meandering pulmonary veins. Pediatric radiology, 45(6), 924-6.
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  Meandering pulmonary veins is a rare clinical entity that can be mistaken for more complex congenital syndromes such as hypogenetic lung syndrome. We report imaging findings in a rare incidentally detected case of bilateral meandering pulmonary veins. We briefly discuss the role of imaging in diagnosing this condition, with particular emphasis on contrast-enhanced CT.
• Udayasankar, U. (2015). Obusez EC, Udayasankar U. Autosomal recessive polycystic kidney disease with caroli syndrome.. J Urol. 2015 Feb;193(2):679-80..
• Udayasankar, U. (2015). Rassi J. Park E, Vachhani N, Karakas SP, Udayasankar U. Diaphragmatic Hernia Beyond the Neonatal Period: Imaging Findings.. Pediatr Radiol (2015) 45 (Suppl 1):S1–S246.
• Udayasankar, U. (2015). Thupili CR, Udyasankar U, Renapurkar R. Bilateral Meandering Pulmonary Veins.. Pediatr Radiol. 2015 Jun;45(6):924-6.
• Udayasankar, U. (2015). Vogelius E, Udayasankar U, Vachhani, N, Lampl B, Mamoun I, Park E, Myers M, Shah S. Preliminary experience with clinical pediatric PET/MRI.. J Nucl Med May 1, 2015 vol. 56 no. supplement 3 420.
• Vogelius, E., Vachhani, N., Udayasankar, U. K., Shah, S. N., Park, E., Myers, M., Mamoun, I., & Lampl, B. S. (2015). Preliminary experience with clinical pediatric PET/MRI. The Journal of Nuclear Medicine, 56, 420-420.
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  420 Objectives To familiarize others with our initial clinical experience with pediatric PET/MRI. This includes our indications, protocols, workflow and radiation savings relative to PET/CT. Methods 29 patients underwent 33 separate clinical PET/MRI studies. The average age was 7.9 years and 52% were male. 64% (21/33) of studies required sedation. 61% (20/33) of studies were performed for the indication of seizure and limited to the brain. The remaining 39% (14/33) of exams were performed for various oncologic follow-up and prior PET/CTs were available for comparison in these cases. Of our exams 88% (29/33) would previously have required 2 separate exams to give the equivalent diagnostic and physiologic information. Majority (84%) of prior CTs were performed using a low dose protocol for attenuation correction but 2 were diagnostic CTs with contrast administration. Dose of FDG administered was recorded as was DLP/dose data for the comparison PET/CTs. Results All exams were considered diagnostic with minimal to no artifact. There was no difference in the dose of FDG utilized in the PET/MR versus PET/CT groups (p = 0.22). The dose savings in the PET/MR group were therefore entirely due to omission of the tomogram/CT images. Dose savings were an average DLP of 132 mGy*cm equating to an effective dose savings of 3.3 mSv in the cases where prior PET/CT was available. Effective dose savings were larger in the two patients with prior diagnostic CTs (6.1 and 10.9 mSv). In addition, by performing 2 previously distinct exams concurrently 55% (18/33) of patients were spared an additional sedation. Conclusions PET/MR can effectively complement existing modalities in both neurological and oncological indications. Effective dose savings relative to PET/CT are relatively modest, particularly compared to attenuation correction only PET/CTs. However, an additional advantage particularly in the pediatric population is the ability to perform 2 exams in one sitting, sparing children multiple sedations and their associated risks.
• Yazdani, M., Park, E., & Udayasankar, U. (2015). Postsurgical diaphragmatic herniation: A rare delayed complication of pediatric intraabdominal surgery. Journal of pediatric surgery.
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  Spontaneous diaphragmatic herniation as a delayed complication of intraabdominal surgery is an exceedingly rare event in children with few cases reported in the literature. Almost all reported cases are on the right side and followed liver transplantation surgery. We present two pediatric cases of spontaneous diaphragmatic herniation as complications of two different abdominal surgeries: pancreatic pseudocyst resection with splenectomy and liver transplantation.
• Udayasankar, U. (2014). Ganni P, Vachhani N, Udayasankar U. Intrauterine testicular torsion.. J Urol. 2014 Jan;191(1):217-8.
• Udayasankar, U. (2014). Udayasankar U: Fetal neuroimaging.. Pediatric neurosciences pathway 2014.
• Vachhani, N., Udayasankar, U. K., & Ganni, P. (2014). Intrauterine testicular torsion.. The Journal of urology, 191(1), 217-8. doi:10.1016/j.juro.2013.10.031
• Udayasankar, U. (2013). Kunam V, Park E, Vachhani N, Udayasankar U. MR evaluation of liver lesions in children with transfusion hemosiderosis.. Pediatr Radiol (2013) 43 (Suppl 2):S205–S458.
• Udayasankar, U. (2013). Wu, F, Park E, Udayasankar U. Cowper Gland Syringocele.. J Urol. 2013 Aug;190(2):713-4..
• Wu, F., Udayasankar, U. K., & Park, E. (2013). Cowper gland syringocele.. The Journal of urology, 190(2), 713-4. doi:10.1016/j.juro.2013.04.079
• Sauer, C. G., Kugathasan, S., Alazraki, A., Applegate, K. E., Kalb, B., Martin, D. R., Middleton, J. P., & Udayasankar, U. K. (2012). Comparison of magnetic resonance enterography with endoscopy, histopathology, and laboratory evaluation in pediatric Crohn disease.. Journal of pediatric gastroenterology and nutrition, 55(2), 178-84. doi:10.1097/mpg.0b013e3182598465
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  Children with Crohn disease (CD) often undergo cross-sectional imaging during clinical evaluation. Magnetic resonance enterography (MRE) is becoming the preferred radiologic assessment due to the lack of radiation exposure; however, there are few data in children with CD comparing MRE with objective disease measures. The aim of the present study was to compare MRE with endoscopy, histopathology, and laboratory evaluation in children with CD..We performed an institutional review board-approved query of our prospective CD MRE database, which includes data in children with CD undergoing MRE since 2008..A total of 147 MRE studies were performed in 119 different children with symptomatic CD. Of those, 53 (39.6%) MRE studies were performed at diagnosis to evaluate small bowel disease burden. A total of 117 (79.6%) MRE studies displayed active and/or chronic disease, whereas 30 (20.4%) MRE studies were normal. When compared with normal MRE studies, active inflammation on MRE was associated with a higher mean C-reactive protein (3.6 vs 1.1, P < 0.001), higher erythrocyte sedimentation rate (36 vs 22, P = 0.0.31), higher platelet value (439 vs 352, P = 0.033), and lower albumin (3.4 vs 3.7, P = 0.049). Comparison between MRE and endoscopy demonstrated excellent agreement when ulcers were present, and moderate agreement with histopathology..Active inflammation on MRE is associated with higher C-reactive protein, erythrocyte sedimentation rate, platelets, and lower albumin in children with CD. MRE displays excellent agreement with endoscopic disease described by ulcers but poor agreement with mild mucosal disease described by erythema and friability. The present study adds to a growing body of evidence that MRE provides excellent assessment of inflammation and measures disease activity in CD.
• Udayasankar, U. (2012). Sauer CG, Middleton JP, Alazraki A, Udayasankar UK, Kalb B, Applegate KE, Martin DR, Kugathasan S. Comparison of magnetic resonance enterography with endoscopy, histopathology, and laboratory evaluation in pediatric crohn disease. .. J Pediatr Gastroenterol Nutr. 2012 Aug;55(2):178-84.
• Li, J., Udayasankar, U. K., Tang, X., Toth, T. L., Small, W. C., & Kalra, M. K. (2011). Patient size compensated automatic tube current modulation in multi-detector row CT of the abdomen and pelvis. Academic radiology, 18(2), 205-11.
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  To evaluate the performance of a patient size-compensated automatic tube current modulation (PSC-AutomA) technique from the perspectives of image quality and radiation dose in multi-detector-row computed tomography (MDCT) scan of the abdomen and pelvis.
• Udayasankar, U. (2011). Li J, Udayasankar UK, Tang X, Toth TL, Small WC, Kalra MK. Patient Size Compensated Automatic Tube Current Modulation in Multidetector Row CT of the Abdomen and Pelvis.. Acad Radiol. 2011 Feb;18(2):205-11.
• Beitler, J. J., Muller, S., Grist, W. J., Corey, A., Klein, A. M., Johns, M. M., Perkins, C. L., Davis, L. W., Udayasanker, U., Landry, J. C., Shin, D. M., & Hudgins, P. A. (2010). Prognostic accuracy of computed tomography findings for patients with laryngeal cancer undergoing laryngectomy. Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 28(14), 2318-22.
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  The indications for upfront laryngectomy in the management of laryngeal cancer are a functionless larynx and extralaryngeal extension. Practically, clinicians rely on imaging to predict which patients will have T4 disease. Our goal was to review the accuracy of preoperative computed tomography (CT) scanning in determining the necessity for initial laryngectomy for advanced laryngeal cancer.
• Udayasankar, U. (2010). Beitler JJ, Muller S, Grist WJ, Corey A, Klein AM, Johns MM, Perkins CL, Davis LW, Udayasankar U, Landry JC, Shin DM, Hudgins PA. Prognostic Accuracy of Computed Tomographic Findings for Patients with Laryngeal Cancer Undergoing Laryngectomy.. J Clin Oncol. 2010 Apr 5..
• Udayasankar, U. (2010). Li J, Udayasankar UK, Carew JC, Small WC. CT guided liver biopsy: Correlation of Procedure Time and Radiation Dose with Patient Size, Weight and Lesion Volume and Depth.. Clin Imaging. 2010 Jul-Aug;34(4):263-8.
• Udayasankar, U. (2010). Li J, Udayasankar UK, Tang X, Carew J, Toth TL, Small WC. An Optimal Contrast Dose Indicator for the Determination of Hepatic Enhancement in Abdominal Multidetector Computed Tomography: Comparison of Patient Attenuation Indicator With Total Body Weight and Body Mass Index. J Comput Assist Tomogr.. 2010 November/December;34(6):874-878..
• Udayasankar, U. (2010). UK Udayasankar, J Li, DA Baumgarten, WC Small, MK Kalra. Response to Letter to the Editor: Acute abdominal pain: value of non-contrast enhanded ultra-low-dose multi-detector row CT as a substitute for abdominal radiographs (N. Buls, K. Nieboer, J. de Mey).. Emergency Radiology 17 (2), 167-168.
• Udayasankar, U. (2010). Udayasankar UK, Alazraki A, Simoneaux SF. Role of PET CT in Congenital Histiocytosis. Pediatr Radiol. 2010 Dec;40 Suppl 1:S57-61.
• Udayasankar, U. K., Alazraki, A. L., & Simoneaux, S. F. (2010). Role of PET/CT in congenital histiocytosis. Pediatric radiology, S57-61.
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  Congenital Langerhans cell histiocytosis (LCH) is a rare, but often severe, form of LCH. Although a more benign single-system congenital LCH has been described, most cases present as multisystem disease with poorer prognosis and are often treated with systemic chemotherapy. Imaging plays a central role in diagnosis, initial staging and assessment of treatment response. PET/CT is increasingly utilized for pediatric LCH. We report a unique case with PET/CT used as an imaging tool in staging and evaluating treatment response in congenital multisystem LCH.
• Udayasankar, U. (2009). Udayasankar UK, Li J, Baumgarten D, Kalra MK, Small WC. Acute abdominal pain: value of non-contrast enhanced ultra-low-dose multi-detector row CT as a substitute for abdominal radiographs.. Emerg Radiol (2009) 16:61–70.
• Martin, D. R., Udayasankar, U. K., Tudorascu, D. L., Sitaraman, S. V., Rutherford, R. E., Martin, D. R., Lauenstein, T. C., & Galloway, J. R. (2008). Role of spectral presaturation attenuated inversion-recovery fat-suppressed T2-weighted MR imaging in active inflammatory bowel disease.. Journal of magnetic resonance imaging : JMRI, 28(5), 1133-40. doi:10.1002/jmri.21574
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  To retrospectively evaluate the efficacy of spectral presaturation attenuated inversion-recovery (SPAIR) fat-suppressed (FS) partial Fourier single shot (SSH) T2-weighted (T2W) and gadolinium-enhanced (Gd) FS 3D-gradient echo (3DGRE) T1-weighted (T1W) delayed phase MRI to differentiate active bowel inflammation from fibrotic disease in patients with Crohn's disease (CD)..MRI studies of 81 patients (mean age, 43 years; range, 22-77 years; M:F ratio 33:48) had T2W and T1W imaging including SPAIR-SSH and delayed Gd-3DGRE. The ability to assess disease activity in bowel segments affected were retrospectively evaluated by a grading scheme based on subjective analysis of signal intensities. These results were compared against the standard clinical parameters of disease activity..SPAIR-SSH images correlated better (r=0.74, P
• Udayasankar, U. (2008). Jayashankar A, Udayasankar U, Sebastian S, Lee EK, Kalra M, Small W. MDCT of thoraco-abdominal trauma: an evaluation of the success and limitations of primary interpretation using multiplanar reformatted images vs axial images.. Emerg Radiol. 2008 Jan;15(1):29-34..
• Udayasankar, U. (2008). Li J, Udayasankar UK, Toth TL, Small WC, Kalra MK. Application of Automatic Vertical Positioning Software to Reduce Radiation Exposure in Multidetector Row Computed Tomography of the Chest.. Invest Radiol. 2008 Jun;43(6):447-452.
• Udayasankar, U. (2008). Udayasankar UK, Braithwaite K, Arvaniti M, Tudorascu D, Small WC, Little S, Palasis S. Low-dose nonenhanced head CT protocol for follow-up evaluation of children with ventriculoperitoneal shunt: reduction of radiation and effect on image quality.. AJNR Am J Neuroradiol. 2008 Apr;29(4):802-6.
• Udayasankar, U. (2008). Udayasankar UK, Chamsuddin A, Mittal P, Small WC. Diagnostic Imaging and Image Guided Interventions in Hepatobiliary malignancies. Cancer Treat Res. 2008;143:199-228. Cancer Treat Res. 2008;143:199-228.
• Udayasankar, U. (2008). Udayasankar UK, Martin DR Lauenstein T, Rutherford R, Galloway J, Sitaraman S. Role of Spectral Presaturation Attenuated Inversion-Recovery Fat-suppressed T2-weighted MR Imaging in Active Inflammatory Bowel Disease.. J Magn Reson Imaging. 2008 Nov;28(5):1133-40.
• Udayasankar, U. (2008). Udayasankar UK, Momin Z, Small WC. 3DPost-Processing technique in MDCT: Principles and Practical Applications. In: Saini S., Rubin GD and Kalra MK (Eds.) MDCT: From Protocols to Practice.. Springer-Verlag, 2008: pp 65-79..
• Udayasankar, U. K., Braithwaite, K., Arvaniti, M., Tudorascu, D., Small, W. C., Little, S., & Palasis, S. (2008). Low-dose nonenhanced head CT protocol for follow-up evaluation of children with ventriculoperitoneal shunt: reduction of radiation and effect on image quality. AJNR. American journal of neuroradiology, 29(4), 802-6.
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  Children with a shunt for hydrocephalus often undergo multiple follow-up head CT scans, increasing the risk for long-term effects of ionizing radiation. The purpose of our study was to evaluate if an unenhanced low-dose head CT could consistently provide acceptable image quality and diagnostic information.
• Udayasankar, U. K., Small, W., Sebastian, S., Lee, E. K., Kalra, M. K., & Jayashankar, A. (2008). MDCT of thoraco-abdominal trauma: an evaluation of the success and limitations of primary interpretation using multiplanar reformatted images vs axial images.. Emergency radiology, 15(1), 29-34. doi:10.1007/s10140-007-0670-5
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  To assess whether independent evaluation of coronal and sagittal reformatted images can replace axial images for primary interpretation of multidetector row computed tomography (MDCT) images in patients with thoraco-abdominal trauma. 111 (M/F 69:42) patients with acute chest or abdominal trauma underwent 16-channel MDCT. Coronal and sagittal multiplanar reformatted (MPR) images were generated from thin-section axial images. Two radiologists independently interpreted the MPR images first followed by axial images for both imaging findings as well as adequacy of image quality. Differences between independent reader review of axial and MPR images were assessed using the Wilcoxon signed rank test. There was no significant difference in soft tissue findings identified on MPR vs axial images for either reader, p = 0.91 and 0.34, respectively. However, both readers identified more skeletal findings on the MPR as compared to the axial images, p = 0.026 and 0.040, respectively. There was no significant difference between the readers in their interpretation of axial (soft tissue, p = 0.56; skeletal, p = 0.65) or MPR (soft tissue, p = 0.32; skeletal, p = 0.65) findings. More skeletal findings were identified during the isolated review of MPR as compared to axial images alone. However, the use of MPR images alone still resulted in an unacceptably high number of missed soft tissue and even skeletal findings. A combined approach where both data sets are simultaneously available is therefore preferred.
• Udayasankar, U. K., Toth, T. L., Small, W. C., Li, J., & Kalra, M. K. (2008). Application of automatic vertical positioning software to reduce radiation exposure in multidetector row computed tomography of the chest.. Investigative radiology, 43(6), 447-52. doi:10.1097/rli.0b013e318169005e
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  To determine the effect of automatic vertical positioning (AVP) software on radiation dose reduction in multidetector row computed tomography of the chest..Two hundred forty-three consecutive patients (mean age, 54; range, 20-93 years), who underwent 64-slice multidetector row computed tomography of the chest from November 2005 to April 2006, were included in this study. This study was approved by our institutional review board with waiver of informed consent. Technologists initially positioned the patient in the gantry by adjusting the table height (vertical positioning) using a laser guidance system and patient surface anatomy. AVP software was then used to determine the true vertical positioning of the patient based on matching the individual patient's mean centroid (center of mass) throughout the chest as determined by the lateral projection with the gantry isocenter and center of the bow-tie filter. The resultant reduction in surface radiation dose with this attenuation-based vertical positioning was then calculated. Software-determined changes in patient vertical positioning and resultant radiation dose savings were analyzed using the t test and Pearson correlation statistics..Vertical positioning of the patients by the technologist differed from AVP with the bow-tie filter in 95.5% (232 of 243) of patients with an average vertical mispositioning distance of 33.2 +/- 1.1 mm (range, 5.1-97 mm). Among mispositioned patients, 97% (225 of 232) were vertically mispositioned below the isocenter with a mean distance of 33.8 +/- 1.1 mm (range, 5.1-97 mm) and 3% (7 of 232) patients were vertically mispositioned above the isocenter, with a mean distance of 12.7 +/- 2.8 mm (range, 6-28 mm). The average surface radiation dose reduction with AVP software was 19% +/- 1% (range, 1%-46.6%). There was a strong correlation between vertical mispositioning distance and the surface radiation dose reduction facilitated by AVP software (r(2) = 0.9, P < 0.001)..AVP software can help in optimum patient vertical positioning leading to substantial reduction in surface radiation dose.
• Udayasankar, U., Chamsuddin, A., Mittal, P., & Small, W. C. (2008). Diagnostic imaging and image-guided interventions of hepatobiliary malignancies. Cancer treatment and research, 143, 199-228.
• Small, W. C., Udayasankar, U. K., Toth, T. L., Seamans, J., Li, J., & Kalra, M. K. (2007). Automatic patient centering for MDCT: effect on radiation dose.. AJR. American journal of roentgenology, 188(2), 547-52. doi:10.2214/ajr.06.0370
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  The purpose of this study was to determine with phantom and patient imaging the effect of an automatic patient-centering technique on the radiation dose associated with MDCT..A 32-cm CT dose index (CTDI) phantom was scanned with 64-MDCT in three positions: gantry isocenter and 30 and 60 mm below the isocenter of the scanner gantry. In each position, surface, peripheral, and volume CTDIs were estimated with a standard 10-cm pencil ionization chamber. The institutional review board approved the study with 63 patients (36 men, 27 women; mean age, 51 years; age range, 22-83 years) undergoing chest (n = 18) or abdominal (n = 45) CT using the z-axis automatic exposure control technique. Each patient was positioned according to the region being scanned and then was centered in the gantry. Before scanning of a patient, automatic centering software was used to estimate patient off-centering and percentage of dose reduction with optimum recentering. Data were analyzed with linear correlation and the Student's t test..Peripheral and surface CTDIs increased approximately 12-18% with 30-mm off-center distance and 41-49% with 60-mm off-center distance. Approximately 95% (60/63) of patients were not positioned accurately in the gantry isocenter. The mean radiation dose saving with automatic centering of all patients was 13.0% +/- 0.9% (range, 2.6-29.9%). There was strong correlation between off-center distance and percentage of surface CTDI reduction with recentering of patients in the gantry isocenter (r2 = 0.85, p < 0.0001)..Surfaces doses can be reduced if radiologic technologists can better center patients within the CT gantry. Automatic centering technique can help in optimum patient centering and result in as much as 30% reduction in surface dose.
• Udayasankar, U. (2007). Li J, Udayasankar UK, Toth TL, Seamans J, Small WC, Kalra MK. Automatic Patient Centering for MDCT: effect on radiation dose.. AJR Am J Roentgenol 2007; 188:547-552.
• Udayasankar, U. (2006). Udayasankar UK, Foreign Body, Air, Stone Targeted (Fast) CT Of The Abdomen And Pelvis In Patients With Acute Abdomen Using An Ultra Low Dose CT Protocol.. Emerg Radiol (2006) 12: 286–300 (290)..
• Udayasankar, U. (2005). Senthil J.Rajappa, Unni Krishnan U, Satish Rao I, Raghunandha Rao, Anjana Surath, Aruna Prayaga. Renal Metastases from Primary Hepatocellular Carcinoma.. Indian Journal of Medical and Pediatric Oncology, Vol 26, No.2, 2005: 37-39.
• Udayasankar, U. (2005). Udayasankar U. Images: Persistent Primitive Trigeminal Artery.. Indian Journal of Radiology and Imaging, April 2005.

Proceedings Publications

• Keerthivasan, M. B., Winegar, B., Udayasankar, U., Bilgin, A., Altbach, M. I., & Saranathan, M. (2018, June). An Optimized Single-shot Sequence for Fast T2W Imaging of the Brain. In 2018 Meeting of the International Society for Magnetic Resonance in Medicine.
• Saranathan, M., Altbach, M. I., Bilgin, A., Udayasankar, U., Winegar, B., & Keerthivasan, M. B. (2018, June). An optimized single-shot sequence for fast T2w imaging of the brain. In ISMRM annual meeting.
• Khan, R., Probst, J., & Udayasankar, U. (2016, May). IAC Fundus Enhancing Pseudolesion: First Reported Incidence on Post Contrast 1mm Volumetric T1 SPACE.. In ASNR 54th Annual Meeting, Washington D.C..
• Saranathan, M., Sharma, P., Udayasankar, U., & Khan, R. (2016, May). Comparison of a novel, motion-robust MPRAGE imaging sequence with conventional MPRAGE imaging.. In ISMRM, 24th Annual Meeting, Singapore.

Presentations

• Keerthivasan, M. B., Winegar, B., Udayasankar, U., Bilgin, A., Altbach, M. I., & Saranathan, M. (2018, June). An optimized single-shot sequence for fast T2w imaging of the brain. ISMRM annual meeting. Paris, France: International Society for Magnetic Resonance in Medicine.
• Udayasankar, U., Gilbertson-Dahdal, D., Desoky, S., & Mostamandy, M. (2020, Spring). Diagnostic Performance of Rapid Unenhanced MRI in Acute Right Lower Quadrant Abdominal Pain in Girls. American Roentgen Ray Society Annual Meeting. Chicago, Illinois: American Roentgen Ray Society.
• Udayasankar, U., Kalb, B. T., Desoky, S. M., Gilbertson-Dahdal, D., & Martin, D. R. (2019, Spring). Non-enhanced MRI of the Abdomen in Comprehensive Evaluation of Acute Abdominal Pain in Children: A Paradigm Shift. American Roentgen Ray Society Annual Meeting. Honolulu, HI: American Roentgen Ray Society.
• Mostamandy, M., Udayasankar, U., Udayasankar, U., Gilbertson-Dahdal, D., Desoky, S., Gilbertson-Dahdal, D., Desoky, S., Gilbertson-Dahdal, D., Desoky, S., Mostamandy, M., Mostamandy, M., & Udayasankar, U. (2020, Spring). Diagnostic Performance of Rapid Unenhanced MRI in Acute Right Lower Quadrant Abdominal Pain in Girls. American Roentgen Ray Society Annual Meeting. Chicago, Illinois: American Roentgen Ray Society.
• Mushtaq, R., Sawyer, D., Udayasankar, U., & Vedantham, S. (2020, May). Accuracy of Resident and Attending radiologist interpretations of abdominopelvic magnetic resonance imaging performed for pediatric acute appendicitis. SPR 2020 Annual Meeting & Postgraduate Course. Miami, FL (virtual): Society of Pediatric Radiology.
• Martin, D. R., Gilbertson-Dahdal, D., Desoky, S. M., Kalb, B. T., & Udayasankar, U. (2019, Spring). Non-enhanced MRI of the Abdomen in Comprehensive Evaluation of Acute Abdominal Pain in Children: A Paradigm Shift. American Roentgen Ray Society Annual Meeting. Honolulu, HI: American Roentgen Ray Society.
• Desoky, S. M., Arteaga, V., Vedantham, S., & Taljanovic, M. (2018, Spring). Comparison of Assessment of Medical Student Knowledge Following a Radiology Rotation by Radiology ExamWeb and Institutionally-created Final Examinations: Are the Exams Compara-ble and Does a Subspecialty Rotation Make a Difference in Performance?. Association of University Radiologists Annual Meeting. Orlando, FL: Association of University Radiologists.
• Mushtaq, R., Desoky, S. M., Morello, F., Gilbertson-Dahdal, D., & Udayasankar, U. (2017, Fall). A Feasibility Study of Performing MRI as the Initial Imaging Modality in Pediatric Acute Appendicitis. American Society of Emergency Radiology Annual Meeting. Toronto, Canada.
• Mushtaq, R., Shareef, F., Desoky, S. M., Gilbertson-Dahdal, D., Morello, F., Kalb, B., Martin, D., & Udayasankar, U. (2017, Fall). Resident Performance in Interpretation of Emergent MRI in Children with Suspected Acute Appendicitis. Radiological Society of North America Annual Meeting. Chicago, IL.
• Mushtaq, R., Shareef, F., Gilbertson-Dahdal, D., Desoky, S. M., Morello, F., Kalb, B. T., Martin, D. R., & Udayasankar, U. (2017, November). MRI as the Initial Imaging Modality of Choice in Children with Suspected Acute Appendicitis: Institutional Experience. Radiological Society of North America. Chicago, IL: RSNA.
• Mushtaq, R., Shereef, F., Gilbertson-Dahdal, D., Morello, F., Desoky, S. M., Kalb, B. T., Martin, D. R., & Udayasankar, U. (2017, November). Resident Performance in Interpretation of Emergent MRI in Children with Suspected Acute Appendicitis. Radiological Society of North America. Chicago, IL: RSNA.
• Udayasankar, U., Gilbertson-Dahdal, D., Morello, F., Desoky, S. M., & Mushtaq, R. (2017, September). A Feasibility study of Performing MRI as the Initial Imaging Modality in Pediatric Acute Appendicitis. American Society of Emergency Radiology. Toronto, ON, Canada: ASER.
• Udayasankar, U. (2016, May). Posterior Fossa Malformations in children. American Roentgen Ray Society Annual Meeting.
• Udayasankar, U. (2016, May). Reconstruction Technique for Reducing Brain CT Radiation Dose: A Study in Pediatric Patients Following Brain Trauma.. American Society of Neuroradiology (ASNR) Annual Meeting. Washington DC.
• Udayasankar, U. (2016, May). Values Prior to and Following Administration of a Gadolinium Based Contrast Agent: A Feasibility Study Using a Modified MOLLI Technique at 1.5 T and 3T. American Society of Neuroradiology (ASNR) Annual Meeting. Washington DC.

Poster Presentations

• Steinmeyer, L., Desoky, S. M., Morello, F., Gilbertson-Dahdal, D., & Udayasankar, U. (2018, May). Colocolic Intussusception in Children with Colonic Polyp as the Lead Point. Society of Pediatric Radiology. Nashville, TN: SPR.
• Udayasankar, U., Gilbertson-Dahdal, D., Desoky, S. M., Karakas, S. P., Barney, N. S., & Alfonso, G. D. (2021, Fall). Acute Imaging Manifestations of Meckel's Diverticulum in Children. Radiological Society of North America Annual Meeting. Chicago, IL.
• Udayasankar, U., Gilbertson-Dahdal, D., Desoky, S. M., Karakas, S. P., Barney, N. S., & Alfonso, G. D. (2021, Fall). Ultrafast Magnetic Resonance Imaging for Acute Pelvic Pain in Girls: Lessons Learned. Radiological Society of North America Annual Meeting. Chicago, IL.
• Kalb, B. T., Martin, D. R., Petkovska, I., & Bhowra, A. (2018, June). Diagnostic accuracy of MR imaging for acute pyelonephritis.. ISMRM. Paris, France: ISMRM.
• Steinmeyer, L., Udayasankar, U., Gilbertson-Dahdal, D., Desoky, S. M., Morello, F., Gilbertson-Dahdal, D., Desoky, S. M., Morello, F., Steinmeyer, L., & Udayasankar, U. (2018, May). Colocolic Intussusception in Children with Colonic Polyp as the Lead Point. Society for Pediatric Radiology Annual Meeting. Nashville, TN: SPR.
• Udayasankar, U., Desoky, S. M., Gilbertson-Dahdal, D., Morello, F., Martin, D. R., & Kalb, B. T. (2018, November). Rapid MRI as a Problem Solver in Challenging Cases of Pediatric Acute Abdominal Pain: Can you make the diagnosis?. RSNA. Chicago, IL: RSNA.
• Udayasankar, U., Forrest, A., Katzman, P., Chaturvedi, A., & Chaturvedi, A. (2018, November). Characterizing Pediatric Liver Masses and Mimics by MR: A Radiologists Primer.. RSNA. Chicago, IL: RSNA.
• Mushtaq, R., Desoky, S. M., Morello, F., Gilbertson-Dahdal, D., & Udayasankar, U. (2017, Fall). Diagnostic Accuracy of Overnight Residents in Interpreting Emergent MRI in Children With Suspected Acute Appendicitis. American Society of Emergency Radiology Annual Meeting. Toronto, Canada.
• Mushtaq, R., Desoky, S. M., Morello, F., Gilbertson-Dahdal, D., & Udayasankar, U. (2017, Fall). Single Institution Experience in performing MRI as the Initial Imaging Modality in the Pediatric Population. University of Arizona College of Medicine Junior Investigator Poster Forum. Tucson, AZ: University of Arizona College of Medicine.
• Mushtaq, R., Shareef, F., Desoky, S. M., Gilbertson-Dahdal, D., Morello, F., Kalb, B., Martin, D., & Udayasankar, U. (2017, Fall). A Feasibility Study of Performing MRI as the Initial Imaging Modality in Pediatric Acute Appendicitis. Radiological Society of North America Annual Meeting. Chicago, IL.
• Patel, V., Hinkel, T., L, F., Winegar, B., Khan, R., Becker, J., & Udayasankar, U. (2017, November). Pain in the Neck: Tales from the ED. Radiological Society of North America. Chicago, IL: RSNA.
• Patel, V., MacKinnon, L., Hinkel, T., Winegar, B., Khan, R., Karakas, P., Park, E., & Udayasankar, U. (2017, November). Ultrasound Imaging of Pediatric Neck Masses: What Radiologists Need To Know.. Radiological Society of North America. Chicago, IL: RSNA.
• Hansra, H., Udayasankar, U., & Desoky, S. M. (2016, December). "Wait! It's Not Appendicitis?" Alternate MRI Diagnoses in Children with Right Lower Quadrant Abdominal Pain. Radiological Society of North America 2016 Annual Meeting. Chicago, IL.
• Hansra, H., Udayasankar, U., & Desoky, S. M. (2016, December). Alternate MRI Diagnoses in Children with Right Lower Quadrant Abdominal Pain. Radiological Society of North America 2016 Annual Meeting. Chicago, IL.
• Udayasankar, U. (2016, May). Comparison of a novel, motion-robust MPRAGE imaging sequence with conventional MPRAGE imaging. American Society of Neuroradiology (ASNR) Annual Meeting. Washington DC.
• Udayasankar, U. (2016, May). Fetal MRI Evaluation of Head and Neck Masses. ARRS. Los Angeles, CA.
• Udayasankar, U. (2016, May). IAC fundus enhancing pseudolesion: First reported incidence on post contrast 1mm volumetric T1 space imaging. American Society of Neuroradiology (ASNR) Annual Meeting. Washington DC.
• Udayasankar, U. (2016, May). Potential Intracranial Gadolinium Deposition in Children following multiple contrast enhanced MRI examinations. Long term parenchymal signal change. American Society of Neuroradiology (ASNR) Annual Meeting. Washington DC.
• Udayasankar, U. (2016, November). Imaging Spectrum of Craniospinal Coccidioidomycosis. Radiological Society of North America Annual Meeting. Chicago, IL.
• Warhadpande, D., Udayasankar, U., & Desoky, S. M. (2016, November). Beyond "Water on the Knee": Imaging Spectrum of Knee Swelling in Children. Radiological Society of North America 2016 Annual Meeting. Chicago, IL.
• Warhadpande, D., Udayasankar, U., & Desoky, S. M. (2016, November). Beyond "Water on the Knee": Imaging Spectrum of Knee Swelling in Children. Radiological Society of North America Annual Meeting. Chicago, IL.
• Warhadpande, D., Udayasankar, U., & Desoky, S. M. (2016, November). Beyond "Water on the Knee: Imaging Spectrum of Knee Swelling in Children. Radiological Society of North America 2016 Annual Meeting. Chicago, IL.
• Winsor, K., Udayasankar, U., & Desoky, S. M. (2016, November). Pearls and Pitfalls in MRI Diagnosis of Ovarian Torsion in Children. Radiological Society of North America Annual Meeting. Chicago, IL.
• Winsor, K., Winsor, K., Udayasankar, U., Udayasankar, U., Desoky, S. M., & Desoky, S. M. (2016, November). Pearls and Pitfalls in MRI Diagnosis of Ovarian Torsion in Children. Radiological Society of North America 2016 Annual Meeting. Chicago, IL.

Case Studies

• Ganni, P., Vachhani, N., & Udayasankar, U. (2014. Intrauterine testicular torsion(pp 217-8).
• Wu, F., Park, E., & Udayasankar, U. (2013. Cowper gland syringocele(pp 713-4).

Others

• Buls, N., Nieboer, K., & de Mey, J. (2010). Comment on article of K. Udayasankar, J. Li, D.A. Baumgarten, W.C. Small, M.K. Kalra: acute abdominal pain:value of non-contrast enhanced ultra-low-dose multi-detector row CT as a substitute for abdominal radiographs (2009). Emergency radiology.
• Udayasankar, U. K., Martin, D., Lauenstein, T., Rutherford, R., Galloway, J., Tudorascu, D., & Sitaraman, S. V. (2008). Role of spectral presaturation attenuated inversion-recovery fat-suppressed T2-weighted MR imaging in active inflammatory bowel disease. Journal of magnetic resonance imaging : JMRI.
  More info

  To retrospectively evaluate the efficacy of spectral presaturation attenuated inversion-recovery (SPAIR) fat-suppressed (FS) partial Fourier single shot (SSH) T2-weighted (T2W) and gadolinium-enhanced (Gd) FS 3D-gradient echo (3DGRE) T1-weighted (T1W) delayed phase MRI to differentiate active bowel inflammation from fibrotic disease in patients with Crohn's disease (CD).