Jonathan R Dillman

Children's Hospital of Michigan, Detroit, Michigan, United States

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Publications (107)268.19 Total impact

  • Brett J Mollard, Ethan A Smith, Jonathan R Dillman
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    ABSTRACT: Magnetic resonance (MR) enterography is an increasingly important pediatric imaging modality that is most often used to evaluate inflammatory bowel disease ( IBD inflammatory bowel disease ), while sparing children and adolescents from potential risks of ionizing radiation exposure. MR enterography allows for evaluation of the bowel lumen and wall, adjacent mesentery and soft tissues, as well as a variety of extraintestinal abdominopelvic IBD inflammatory bowel disease manifestations. While MR enterography can be used to initially confirm the diagnosis of IBD inflammatory bowel disease , particularly small bowel Crohn disease, it has also proven useful in assessing the degree inflammatory activity over time, serving as a radiologic biomarker for response to medical therapy, and identifying a variety of disease-related complications, including strictures, fistulae, and abscesses. The purpose of this review article is to provide radiologists with a systematic approach for MR enterography review and interpretation in children and adolescents with known or suspected of having IBD inflammatory bowel disease and to illustrate both common and infrequent but important imaging findings. Additionally, the authors will present their well-established and clinically successful pediatric MR enterography protocol, up-to-date clinical indications for MR enterography, and briefly mention the role of MR enterography in assessing non- IBD inflammatory bowel disease abnormalities affecting the bowel. Online supplemental material is available for this article . © RSNA, 2015.
    Radiology 01/2015; 274(1):29-43. · 6.21 Impact Factor
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    ABSTRACT: PurposeTo compare the abilities of magnetization transfer magnetic resonance imaging (MT-MRI) and T2-weighted signal intensity (T2WSI) ratios to detect intestinal fibrosis in a Crohn's disease animal model.Materials and Methods Ten rats ("Group 1") received one trinitrobenzenesulfonic acid enema to induce acute colonic inflammation, while 10 additional animals ("Group 2") received multiple enemas to induce colonic inflammation and fibrosis. Gradient recalled-echo MT-MRI (5 and 10 kHz off-resonance) and T2-weighted spin-echo imaging were performed 2 days after the last enema. MT ratios (MTR) and T2WSI ratios were calculated in the area of greatest colonic thickening. Bowel wall MTR, bowel wall MTR normalized to paraspinous muscle MTR ("normalized MTR"), and T2WSI ratios were compared between animal groups using Student's t-test.ResultsAt 10 kHz off-resonance, mean bowel wall MTR for Group 1 was 24.8 ± 3.1% vs. 30.3 ± 3.2% for Group 2 (P = 0.001). Mean normalized MTR was 0.45 ± 0.05 for Group 1 and 0.58 ± 0.08 for Group 2 (P = 0.0003). At 5 kHz off-resonance, mean bowel wall MTR for Group 1 was 34.7 ± 5.2% vs. 40.3 ± 3.6% for Group 2 (P = 0.015). Mean normalized MTR was 0.53 ± 0.08 for Group 1 and 0.64 ± 0.07 for Group 2 (P = 0.003). Mean T2WSI ratio was 5.32 ± 0.98 for Group 1 and 3.01 ± 0.66 for group 2 (P < 0.0001). Mean T2WSI ratio/MTR (10 kHz off-resonance) was 12.06 ± 2.70 for Group 1 and 5.22 ± 1.29 for Group 2 (P < 0.0001), with an ROC c-statistic of 0.98.ConclusionMTR and T2WSI ratios detect bowel wall fibrosis in a Crohn's disease animal model. J. Magn. Reson. Imaging 2014.
    Journal of Magnetic Resonance Imaging 12/2014; · 2.57 Impact Factor
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    ABSTRACT: To determine whether bowel wall fibrosis can be detected in freshly resected human intestinal specimens based on ultrasound-derived shear wave speed. Seventeen intact (>3-cm) bowel segments (15 small and 2 large intestine) from 12 patients with known or suspected inflammatory bowel disease were procured immediately after surgical resection. Ultrasound shear wave elastography of the bowel wall was performed by two methods (Virtual Touch Quantification [VTQ] and Virtual Touch-IQ [VT-IQ]; Siemens Medical Solutions USA, Inc, Mountain View, CA). Eighteen short-axis shear wave speed measurements were acquired from each specimen: 3 from the 9-, 12-, and 3-o'clock locations for each method. Imaging was performed in two areas for specimens greater than 10 cm in length (separated by ≥5 cm). A gastrointestinal pathologist scored correlative histologic slides for inflammation and fibrosis. Differences in mean shear wave speed between bowel segments with low and high inflammation/fibrosis scores were assessed by a Student t test. Receiver operating characteristic curve analysis was performed. High-fibrosis score (n = 11) bowel segments had a significantly greater mean shear wave speed than low-fibrosis score (n = 6) bowel segments (mean ± SD: VTQ, 1.59 ± 0.37 versus 1.18 ± 0.08 m/s; P= .004; VT-IQ, 1.87 ± 0.44 versus 1.50 ± 0.26 m/s; P= .049). There was no significant difference in mean shear wave speed between high-and low-inflammation score bowel segments (P > .05 for both VTQ and VT-IQ). Receiver operating characteristic curves showed areas under the curve of 0.91 (95% confidence interval, 0.67-0.99) for VTQ and 0.77 (95% confidence interval, 0.51-0.94) for VT-IQ in distinguishing low-from high-fibrosis score bowel segments. Ex vivo bowel wall shear wave speed measurements increase when transmural intestinal fibrosis is present. © 2013 by the American Institute of Ultrasound in Medicine.
    Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 12/2014; 33(12):2115-23. · 1.53 Impact Factor
  • 2014 American Academy of Pediatrics National Conference and Exhibition; 10/2014
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    ABSTRACT: There is a paucity of data available regarding the repeatability and reproducibility of superficial shear wave speed (SWS) measurements at imaging depths relevant to the pediatric population.
    Pediatric Radiology 09/2014; · 1.65 Impact Factor
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    ABSTRACT: Biliary atresia is a rapidly progressive liver disease necessitating prompt diagnosis and surgical intervention, so it must be promptly distinguished from other neonatal/infantile liver diseases.
    Pediatric Radiology 09/2014; · 1.65 Impact Factor
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    ABSTRACT: Head trauma is a frequent indication for cranial imaging in children. CT is considered the first line of study for suspected intracranial injury because of its wide availability and rapid detection of acute hemorrhage. However, the majority of childhood head injuries occur without neurologic complications, and particular consideration should be given to the greater risks of ionizing radiation in young patients in the decision to use CT for those with mild head trauma. MRI can detect traumatic complications without radiation, but often requires sedation in children, owing to the examination length and motion sensitivity, which limits rapid assessment and exposes the patient to potential anesthesia risks. MRI may be helpful in patients with suspected nonaccidental trauma, with which axonal shear injury and ischemia are more common and documentation is critical, as well as in those whose clinical status is discordant with CT findings. Advanced techniques, such as diffusion tensor imaging, may identify changes occult by standard imaging, but data are currently insufficient to support routine clinical use. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.
    Journal of the American College of Radiology: JACR 08/2014;
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    ABSTRACT: Objective Imaging of patients with multicystic dysplastic kidney (MCDK) has increased over the past three decades. This increased use of imaging has provided additional insights into the natural history of MCDK. The present study looked at this data for predictors of involution and associated anomalies. Methods and materials Institutional review board approval was obtained for this retrospective study. The University of Michigan Departments of Urology and Radiology records were searched to identify unilateral MCDK patients during 1980–2012. Available clinical, radiological and surgical records were reviewed, and pertinent data were recorded. The log-rank test and a Cox proportional regression analysis were performed to identify predictors of MCDK involution. Probability of involution over time was assessed using Kaplan-Meier methodology. Results 301 unilateral MCDKs were identified; 195 (64.8%) were detected antenatally. Of the MCDKs found, 136 (45.2%) were in girls; 160 (53.2%) were right-sided. Mean size at baseline was 5.0 ± 0.2 cm (Mean ± SE). Associated abnormalities included: contralateral ureteropelvic junction obstruction (n = 10; 3.3%); contralateral ureterovesical junction obstruction/primary megaureter (n = 6; 2.0%); ipsilateral VUR (n = 21; 7.0%); contralateral VUR (n = 63; 20.1%); and renal fusion anomaly (n = 4; 1.3%). The cumulative probability of involution was: 9.8% at one year, 38.5% at five years, and 53.5% at ten years of age. Baseline MCDK size was the only significant predictor of involution at bivariate (p < 0.0001) and multivariate (p < 0.0001; HR 0.58 [95% CI: 0.49, 0.69]) analyses. No MCDK developed malignancy during the follow-up period. Conclusion As many MCDKs eventually involute and the risk of associated malignancy appears to be very low, there is no absolute indication for nephrectomy. Based on the data and other recent studies, it is believed that pediatric MCDK patients with no other urologic abnormalities can safely tolerate more limited urological and radiological follow-up.
    Journal of Pediatric Urology 08/2014; · 1.41 Impact Factor
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    ABSTRACT: The purpose of our investigation was to determine the frequency of proximate acute and chronic confounding risk factors for acute kidney injury (AKI) in a cohort of adult hospitalized patients with stable renal function who developed AKI following an intravenous (IV) contrast-enhanced computed tomography (CT) examination. Institutional review board approval was obtained for this retrospective, Health Insurance Portability and Accountability Act-compliant investigation. Overall, 100 adult inpatients (50 males [mean age = 61 years, range: 24-94 years] and 50 females [mean age = 60 years, range: 20-95 years]) with stable pre-CT renal function who developed post-CT AKI using the Acute Kidney Injury Network (AKIN) laboratory criteria following an IV contrast-enhanced CT examination comprised the study population. Electronic International Classification of Disease-9 analysis followed by a comprehensive manual electronic medical record review was systematically performed by 5 radiologists to identify known acute (n = 24, within 5 days before or 3 days after CT) and chronic (n = 21) risk factors for AKI other than contrast material administration that might confound a diagnosis of contrast-induced nephrotoxicity. Descriptive statistics were performed. Of 100 inpatients with post-CT AKI, 99 (99%) had 1 or more acute risk factor(s) for AKI other than contrast material administration (median = 3 risk factors, range: 0-8) and 86 (86%) had one or more chronic risk factor(s) for AKI (median = 2 risk factors, range: 0-7). The median number of risk factors (acute or chronic) per patient was 5 (range: 1-13). Only 1 inpatient (1%) developed post-CT AKI without a confounding acute risk factor (estimated glomerular filtration rate = 62-71mL/min/1.73m(2), 4 chronic risk factors, and CT 7 days after pancreaticoduodenectomy). The most common acute risk factors were nephrotoxic medications (83%) and parenteral blood product administration (30%). The most common chronic risk factors were hypertension (59%) and chronic kidney disease (56%). Nonconfounded post-CT AKI is rare in hospitalized adults with stable renal function who have been exposed to IV low- or iso-osmolality iodinated contrast material.
    Current Problems in Diagnostic Radiology 06/2014;
  • Ethan A Smith, Patricia K Castelli, Jonathan R Dillman
    Pediatric Radiology 04/2014; · 1.65 Impact Factor
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    ABSTRACT: PURPOSE/AIM To provide a basic introduction to pediatric MR urography (MRU) technique, clinical indications, and a systematic approach to review/interpretation.To provide a basic introduction to the technical basis of pediatric MRU as well as a systematic approach to interpreting MRU. CONTENT ORGANIZATION We will present: -Pediatric MRU technique and clinical indications. -Data provided by MRU in children, including: Anatomy of renal parenchyma, collecting systems, ureters, and the bladder. Functional assessment, based on renal contrast material uptake and excretion. -Advantages and disadvantages of MRU compared to other kidney/urinary tract imaging methods. -Systematic approach for MRU review/interpretation. -Numerous case-based examples of normal and abnormal anatomy/function, including complex/difficult cases where MRU affected clinical management. SUMMARY MRU is a useful tool for depicting both anatomy and function of the pediatric kidneys and urinary system. The technique can demonstrate abnormalities that are difficult to understand using conventional imaging modalities, and it can provide comprehensive evaluation minimizing the need for multiple imaging studies. This educational exhibit will demonstrate the clinical value of pediatric MRU and provide the audience with a basic approach to reviewing/ interpreting these exams..
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • Article: Preface.
    Jonathan R Dillman, Ethan A Smith
    Magnetic resonance imaging clinics of North America 11/2013; 21(4):xv-xvii.
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    ABSTRACT: Duplex renal collecting systems are common congenital anomalies of the upper urinary tract. In most cases they are incidental findings and not associated with additional pathologies. They demonstrate, however, higher incidences of hydroureteronephrosis, ureteroceles, and ectopic ureters. The most comprehensive morphologic and functional evaluation of duplex systems can be achieved using magnetic resonance urography. Functional magnetic resonance urography allows better separation of the renal poles, thus more accurate calculation of the differential renal functions compared with renal scintigraphy. Magnetic resonance urography is the study of choice when upper urinary tract anatomy is complex or when functional evaluation is needed.
    Magnetic resonance imaging clinics of North America 11/2013; 21(4):717-30.
  • Nathan D Egbert, David A Bloom, Jonathan R Dillman
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    ABSTRACT: Magnetic resonance cholangiopancreatography (MRCP) is an extremely useful tool for evaluating a wide variety of disorders affecting the pancreaticobiliary system in neonates/infants, children, and adolescents. This imaging technique has numerous distinct advantages over alternative diagnostic modalities, such as endoscopic retrograde cholangiopancreatography and percutaneous transhepatic cholangiography, including its noninvasive nature and lack of ionizing radiation. Such advantages make MRCP the preferred first-line method for advanced imaging the pediatric pancreaticobiliary tree, after ultrasonography. This article presents a contemporary review of the use of MRCP in the pediatric population, including techniques, indications, and the imaging appearances of common and uncommon pediatric disorders.
    Magnetic resonance imaging clinics of North America 11/2013; 21(4):681-96.
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    ABSTRACT: Noninvasive, nonionizing, multiparametric magnetic resonance (MR) imaging of the pelvis using a field strength of 3 T now provides a comprehensive assessment of perineal involvement in pediatric Crohn disease. MR imaging accurately evaluates inflammatory disease activity, and allows determination of the number and course of fistula tracts as well as their relationships to vital perianal structures, including the external anal sphincter, helping to guide surgical management and improve outcomes. This article provides an up-to-date review of perineal MR imaging findings of Crohn disease in the pediatric population, including fistulous disease, abscesses, and skin manifestations. Imaging technique is also discussed.
    Magnetic resonance imaging clinics of North America 11/2013; 21(4):813-28.
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    ABSTRACT: Purpose:To retrospectively compare image quality and radiation dose between a reduced-dose computed tomographic (CT) protocol that uses model-based iterative reconstruction (MBIR) and a standard-dose CT protocol that uses 30% adaptive statistical iterative reconstruction (ASIR) with filtered back projection.Materials and Methods:Institutional review board approval was obtained. Clinical CT images of the chest, abdomen, and pelvis obtained with a reduced-dose protocol were identified. Images were reconstructed with two algorithms: MBIR and 100% ASIR. All subjects had undergone standard-dose CT within the prior year, and the images were reconstructed with 30% ASIR. Reduced- and standard-dose images were evaluated objectively and subjectively. Reduced-dose images were evaluated for lesion detectability. Spatial resolution was assessed in a phantom. Radiation dose was estimated by using volumetric CT dose index (CTDIvol) and calculated size-specific dose estimates (SSDE). A combination of descriptive statistics, analysis of variance, and t tests was used for statistical analysis.Results:In the 25 patients who underwent the reduced-dose protocol, mean decrease in CTDIvol was 46% (range, 19%-65%) and mean decrease in SSDE was 44% (range, 19%-64%). Reduced-dose MBIR images had less noise (P > .004). Spatial resolution was superior for reduced-dose MBIR images. Reduced-dose MBIR images were equivalent to standard-dose images for lungs and soft tissues (P > .05) but were inferior for bones (P = .004). Reduced-dose 100% ASIR images were inferior for soft tissues (P < .002), lungs (P < .001), and bones (P < .001). By using the same reduced-dose acquisition, lesion detectability was better (38% [32 of 84 rated lesions]) or the same (62% [52 of 84 rated lesions]) with MBIR as compared with 100% ASIR.Conclusion:CT performed with a reduced-dose protocol and MBIR is feasible in the pediatric population, and it maintains diagnostic quality.© RSNA, 2013Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13130362/-/DC1.
    Radiology 10/2013; · 6.21 Impact Factor
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    ABSTRACT: Renal Doppler US is used to evaluate suspected vascular causes of hypertension in children, despite mostly unknown diagnostic performance characteristics. To evaluate renal Doppler US for detecting vascular causes of hypertension in children with high clinical suspicion of aortic or renal artery narrowing. We identified pediatric renal Doppler US examinations performed for hypertension between January 1995 and June 2010 at our institution. We excluded children without follow-up angiography (CT-, MR-, or catheter-based). Two pediatric radiologists reviewed imaging studies and documented relevant findings. Intrarenal spectral Doppler resistive index measurement <0.5 or tardus parvus waveform constituted a positive examination. Thirty-five boys and 13 girls underwent renal Doppler US and confirmatory imaging (mean age = 9.0 years). Nineteen US examinations were truly negative, two were falsely negative, 18 were truly positive (16 involved narrowing of the aorta or main renal artery) and nine were falsely positive. Sonography had a sensitivity and specificity of 90% and 68%, respectively, for detecting a vascular cause of hypertension. Renal Doppler sonography reliably detects renin-mediated hypertension caused by aortic or main renal artery narrowing in children. More studies are needed to determine its ability to detect intrarenal and accessory renal artery stenoses.
    Pediatric Radiology 09/2013; · 1.65 Impact Factor
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    ABSTRACT: Restricted diffusion on diffusion-weighted imaging (DWI) sequences during magnetic resonance enterography (MRE) has been shown in segments of bowel affected by Crohn disease. However, the exact meaning of this finding, particularly within the pediatric Crohn disease population, is poorly understood. The purpose of this study was to determine the significance of bowel wall restricted diffusion in children with small bowel Crohn disease by correlating apparent diffusion coefficient (ADC) values with other MRI markers of disease activity. A retrospective review of pediatric patients (≤ 18 years of age) with Crohn disease terminal ileitis who underwent MRE with DWI at our institution between May 1, 2009 and May 31, 2011 was undertaken. All of the children had either biopsy-proven Crohn disease terminal ileitis or clinically diagnosed Crohn disease, including terminal ileal involvement by imaging. The mean minimum ADC value within the wall of the terminal ileum was determined for each examination. ADC values were tested for correlation/association with other MRI findings to determine whether a relationship exists between bowel wall restricted diffusion and disease activity. Forty-six MRE examinations with DWI in children with terminal ileitis were identified (23 girls and 23 boys; mean age, 14.3 years). There was significant negative correlation or association between bowel wall minimum ADC value and established MRI markers of disease activity, including degree of bowel wall thickening (R = (-)0.43; P = 0.003), striated pattern of arterial enhancement (P = 0.01), degree of arterial enhancement (P = 0.01), degree of delayed enhancement (P = 0.045), amount of mesenteric inflammatory changes (P < 0.0001) and presence of a stricture (P = 0.02). ADC values were not significantly associated with bowel wall T2-weighted signal intensity, length of disease involvement or mesenteric fibrofatty proliferation. Increasing bowel wall restricted diffusion (lower ADC values) is associated with multiple MRI findings that are traditionally associated with active inflammation in pediatric small bowel Crohn disease.
    Pediatric Radiology 09/2013; 43(9):1077-85. · 1.65 Impact Factor
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    ABSTRACT: OBJECTIVE. The purpose of this study was to retrospectively evaluate diagnostic imaging trends and radiation exposure in pediatric inflammatory bowel disease (IBD) at a U.S. academic children's hospital between 2001 and 2010. MATERIALS AND METHODS. Pediatric IBD patients within our health system during the 2001, 2006, and 2010 calendar years were identified. The number of abdominopelvic radiologic and endoscopic examinations (total and by modality) performed during each 1-year-period was recorded for each subject. Means were compared using the Wilcoxon rank sum test. The cumulative lifetime number of diagnostic examinations by modality and estimated effective radiation dose (using Monte Carlo simulation software and CT dose-length product values) was calculated for the 2010 IBD subject cohort. RESULTS. There was a 53% increase in the average number of abdominopelvic diagnostic examinations obtained per pediatric IBD patient comparing 2001 with 2010 (1.29 ± 2.19 vs 1.98 ± 3.46, p = 0.004). Abdominal radiography (p = 0.02), MRI (p < 0.0001), and esophagogastroduodenoscopy (EGD) (p = 0.01) showed significantly increased use. The increase in use of CT and ileocolonoscopy was not significant (p > 0.05). There was significantly reduced use of contrast enema, small-bowel follow-through (SBFT), and upper gastrointestinal (UGI) series (all, p < 0.0001). The average pediatric IBD patient seen in 2010 (mean age, 13.9 years) had undergone 1.08 CT, 0.82 MRI, 1.36 abdominal radiographic, 0.14 contrast enema, 0.52 SBFT, 0.54 UGI, 1.00 ileocolonoscopy, and 0.72 EGD examinations during his or her lifetime, with an average cumulative lifetime estimated effective radiation dose of 4.6 mSv. CONCLUSION. Although the number of yearly diagnostic examinations performed for pediatric IBD patients increased significantly between 2001 and 2010, the cumulative lifetime estimated effective radiation dose is relatively low in most of these patients.
    American Journal of Roentgenology 07/2013; 201(1):W133-40. · 2.74 Impact Factor
  • Matthew R Hammer, Daniel J Podberesky, Jonathan R Dillman
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    ABSTRACT: Advanced multidetector computed tomographic and magnetic resonance imaging techniques (CT and MR enterography, respectively), designed to provide detailed images of the bowel and mesentery, can be successfully performed in children of all ages, frequently without sedation. Cross-sectional enterography allows for noninvasive diagnosis, detection of various disease-related complications and extraintestinal manifestations, and monitoring of bowel-wall inflammation in pediatric inflammatory bowel disease (IBD). This article provides a contemporary review of CT and MR enterography in the pediatric population, including up-to-date techniques and clinical applications. A range of bowel abnormalities is illustrated, with an emphasis on IBD and its many abdominopelvic manifestations.
    Radiologic Clinics of North America 07/2013; 51(4):615-36. · 1.83 Impact Factor

Publication Stats

579 Citations
268.19 Total Impact Points

Institutions

  • 2014
    • Children's Hospital of Michigan
      Detroit, Michigan, United States
  • 2008–2014
    • University of Michigan
      • • Division of Gastroenterology
      • • Department of Radiology
      Ann Arbor, Michigan, United States
    • Concordia University–Ann Arbor
      Ann Arbor, Michigan, United States
  • 2007
    • Washington & Lee University
      Lexington, Virginia, United States