Bowel Wall Visualization Using MR Enterography in Relationship to Bowel Lumen Contents and Patient Demographics.

BACKGROUND: MR enterography (MRE) is generally performed without bowel preparation, but the frequency and extent by which bowel contents affect bowel wall visualization are poorly described in the literature. PURPOSE: To evaluate MRE bowel wall visualization quality relative to bowel lumen contents and patient demographics. STUDY TYPE: Retrospective, single-center. POPULATION: One hundred and four consecutive patients (mean age 29 years, range 5-76 years) without prior bowel resection who had undergone MRE. FIELD STRENGTH/SEQUENCE: 3 T (N = 87) or 1.5 T (N = 17)/T2-weighted single-shot spin echo (T2WI) and fat-saturated T1-weighted gradient echo (T1WI) without and with gadolinium. ASSESSMENT: For the proximal and distal jejunum and ileum and colon, three readers independently categorized bowel lumen signal (water = bright T2 dark T1, T1-bright, or air = dark T2 and T1 signal) and scored distension (0 = poor, 1 = moderate, 2 = well) and wall enhancement (0 = unclear, 1 = perceptible, 2 = clear) based upon gadolinium enhanced T1WI for the 104 MRE exams). The bowel visualization score was the sum of the wall enhancement and distension scores and was considered adequate if ≥3. STATISTICAL TESTS: Wilcoxon signed-rank test. RESULTS: The bowel lumen content was water signal in 93% (97/104 scans), 92% (95/104), 98% (102/104), and 93% (92/104) of the proximal and distal jejunum and proximal and distal ileum, respectively, but only in 12.5% (13/104) of the colon. There was adequate bowel visualization of 53.8%, 77.8%, 84.6%, 90.4% of the proximal and distal jejunum and proximal and distal ileum, respectively, but only 19.2% of the colon. In children (age < 18 years), the visualization score of the ileum was lower when the adjacent colon contained air (2.4 ± 0.97) compared to water (3.75 ± 0.29, P < 0.05) or T1-bright material (3.21 ± 0.82, P < 0.05). DATA CONCLUSION: Without bowel preparation, colon wall visualization was often unsatisfactory at MRE, and air-filled colon also degraded small bowel visualization, particularly in children. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 1.

How to choose an abdominal imaging fellowship.

Radiologists in training draw from their early experiences in residency when choosing a fellowship. Once they have decided on an abdominal imaging fellowship, applicants must learn to navigate the interview process. During this challenging time, applicants explore the difference in clinical curricula and rotations, meet potential mentors and clinical faculty, consider potential academic interests and projects, and choose what location they would like to train for one year after residency. When in training, fellows undergo the challenge of finding employment while learning new skills and refining their abilities to become a well-rounded radiologist and clinician. This article summarizes key points potential applicants should consider when deciding on an abdominal imaging fellowship, how to prepare for the interview season, and how to plan their fellowship year before fellows take the next step to becoming attendings.

Acute diverticulitis: Key features for guiding clinical management.

Diverticular disease of the colon and small bowel is an important cause of pathology leading to emergency department visits and urgent gastrointestinal surgery. CT is a highly sensitive and specific modality for the diagnosis of acute diverticulitis and its complications as well as for the exclusion of alternate causes of pathology. Ultrasound, MRI and virtual CT colonoscopy have important adjunct roles for screening and workup of complications in specific patient populations. While diverticular disease most commonly involves the descending and sigmoid colon, it can also affect the proximal colon and small bowel. Acute diverticulitis may be categorized as uncomplicated or complicated according to the degree of inflammatory changes and related complications it induces, although some degree of overlap exists in clinical practice. Uncomplicated diverticulitis is classically characterized by localized inflammation surrounding a diverticulum ranging from wall thickening and phlegmonous change to the development of small, localized pericolic abscesses. Complicated forms of disease manifest with larger pericolic and distant abscesses, fistulae to adjacent organs, perforation, and peritonitis. Recurrent episodes of diverticulitis may lead to muscular hypertrophy of the bowel wall and luminal narrowing, potentially leading to bowel obstruction. Several imaging features may help to differentiate diverticulitis from colonic malignancy, however this remains a diagnostic imaging challenge that often requires further evaluation with colonoscopy. In this review, we discuss the pathophysiology and key imaging features of acute diverticulitis and its complications. We explore both common and uncommon presentations of the disease involving the colon and small bowel, acute and chronic manifestations of disease, and pitfalls to recognize when imaging alone may be insufficient to distinguish benign from malignant.