Beyond the Bowel: Extraintestinal Manifestations of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic, relapsing immune-mediated inflammation of the gastrointestinal tract. IBD includes two major disease entities: Crohn disease and ulcerative colitis. Imaging plays an important role in the diagnosis and surveillance of these complex disorders. Computed tomographic and magnetic resonance enterographic techniques have been refined in recent years to provide a superb means of evaluating the gastrointestinal tract for suspected IBD. Although the intestinal imaging manifestations of IBD have been extensively discussed in the radiology literature, extraintestinal imaging manifestations of IBD have received less attention. Multiple extraintestinal manifestations may be seen in IBD, including those of gastrointestinal (hepatobiliary and pancreatic), genitourinary, musculoskeletal, pulmonary, cardiac, ocular, and dermatologic disorders. Although many associations between IBD and extraintestinal organ systems have been well established, other associations have not been fully elucidated. Some extraintestinal disorders may share a common pathogenesis with IBD. Other extraintestinal disorders may occur as a result of unintended treatment-related complications of IBD. Although extraintestinal disorders within the abdomen and pelvis may be well depicted with cross-sectional enterography, other musculoskeletal and thoracic disorders may be less evident with such examinations and may warrant further investigation with additional imaging examinations or may be readily apparent from the findings at physical examination. Radiologists involved in the interpretation of IBD imaging examinations must be aware of potential extraintestinal manifestations, to provide referring clinicians with an accurate and comprehensive profile of patients with these complex disorders. © RSNA, 2017.

Adipose tissue MRI for quantitative measurement of central obesity.

PURPOSE: To validate adipose tissue magnetic resonance imaging (atMRI) for rapid, quantitative volumetry of visceral adipose tissue (VAT) and total adipose tissue (TAT). MATERIALS AND METHODS: Data were acquired on normal adults and clinically overweight girls with Institutional Review Board (IRB) approval/parental consent using sagittal 6-echo 3D-spoiled gradient-echo (SPGR) (26-sec single-breath-hold) at 3T. Fat-fraction images were reconstructed with quantitative corrections, permitting measurement of a physiologically based fat-fraction threshold in normals to identify adipose tissue, for automated measurement of TAT, and semiautomated measurement of VAT. TAT accuracy was validated using oil phantoms and in vivo TAT/VAT measurements validated with manual segmentation. Group comparisons were performed between normals and overweight girls using TAT, VAT, VAT-TAT-ratio (VTR), body-mass-index (BMI), waist circumference, and waist-hip-ratio (WHR). RESULTS: Oil phantom measurements were highly accurate (<3% error). The measured adipose fat-fraction threshold was 96% ± 2%. VAT and TAT correlated strongly with manual segmentation (normals r(2) ≥ 0.96, overweight girls r(2) ≥ 0.99). VAT segmentation required 30 ± 11 minutes/subject (14 ± 5 sec/slice) using atMRI, versus 216 ± 73 minutes/subject (99 ± 31 sec/slice) manually. Group discrimination was significant using WHR (P < 0.001) and VTR (P = 0.004). CONCLUSION: The atMRI technique permits rapid, accurate measurements of TAT, VAT, and VTR.

Splenomegaly: A Combined Clinical and Radiologic Approach to the Differential Diagnosis.

An enlarged spleen (splenomegaly) is a common imaging finding and may be related to a broad array of underlying conditions. The multifaceted functions of the spleen make it susceptible to involvement by a variety of pathophysiologic processes. Understanding these conditions and incorporating all relevant clinical and radiologic data allow narrowing the differential diagnosis.