Ratio of visceral to subcutaneous fat area is a biomarker of complicated Crohn's disease.

BACKGROUND & AIMS: Fat wrapping and mesenteric hypertrophy are characteristics of Crohn's disease (CD). In patients with CD, mesenteric adipose tissue releases higher levels of adiponectin, which could up-regulate production of tumor necrosis factor-α and increase the risk for aggressive disease. We investigated whether a higher ratio of visceral to subcutaneous fat was associated with complicated (fistulating or stricturing) CD. METHODS: We identified patients with a confirmed diagnosis of CD who had computed tomography scans of their abdomens (n = 50). Areas of subcutaneous and visceral fat were measured in 1 cross-sectional scan that was taken at the level of the umbilicus. The mesenteric fat index (MFI), defined as the ratio of areas of visceral to subcutaneous fat, was compared between patients with complicated (strictures and fistulas) and inflammatory CD. RESULTS: The mean age of the patients with complications (n = 29) was 49.3 ± 15.6 years, and in patients with inflammatory CD (n = 21) it was 37.7 ± 19.1 years. The MFI was significantly higher (P = .001) in patients with complicated disease (0.67 ± 0.29) than in those with uncomplicated disease (0.23 ± 0.10) and was the only variable that remained significantly different on multivariate analysis. The area under the receiver operating curve for the MFI was 0.95 (95% confidence interval, 0.89-1.0), and an MFI of 0.29 identified patients with complicated CD with 93% sensitivity and 81% specificity. CONCLUSIONS: A high ratio of areas of visceral to subcutaneous fat (MFI) is a marker of aggressive CD. Further studies are needed to determine the roles of adipose tissue in pathogenesis of CD.

Laparoscopic cholecystectomy: postoperative imaging.

OBJECTIVE: The purpose of this article is to describe the imaging findings after laparoscopic cholecystectomy, including the normal postoperative findings and the typical appearances of major complications. The relative merits of the imaging techniques available are discussed. CONCLUSION: Laparoscopic cholecystectomy is a commonly performed surgical procedure and radiologists are often called on to identify or rule out postoperative complications. In such cases, the correct diagnosis is crucial in optimizing patient management.

Prostate cancer localization with endorectal MR imaging and MR spectroscopic imaging: effect of clinical data on reader accuracy.

PURPOSE: To determine the effect of digital rectal examination findings, sextant biopsy results, and prostate-specific antigen (PSA) levels on reader accuracy in the localization of prostate cancer with endorectal magnetic resonance (MR) imaging and MR spectroscopic imaging. MATERIALS AND METHODS: This was a retrospective study of 37 patients (mean age, 57 years) with biopsy-proved prostate cancer. Transverse T1-weighted, transverse high-spatial-resolution, and coronal T2-weighted MR images and MR spectroscopic images were obtained. Two independent readers, unaware of clinical data, recorded the size and location of suspicious peripheral zone tumor nodules on a standardized diagram of the prostate. Readers also recorded their degree of diagnostic confidence for each nodule on a five-point scale. Both readers repeated this interpretation with knowledge of rectal examination findings, sextant biopsy results, and PSA level. Step-section histopathologic findings were the reference standard. Logistic regression analysis with generalized estimating equations was used to correlate tumor detection with clinical data, and alternative free-response receiver operating characteristic (AFROC) curve analysis was used to examine the overall effect of clinical data on all positive results. RESULTS: Fifty-one peripheral zone tumor nodules were identified at histopathologic evaluation. Logistic regression analysis showed awareness of clinical data significantly improved tumor detection rate (P <.02) from 15 to 19 nodules for reader 1 and from 13 to 19 nodules for reader 2 (27%-37% overall) by using both size and location criteria. AFROC analysis showed no significant change in overall reader performance because there was an associated increase in the number of false-positive findings with awareness of clinical data, from 11 to 21 for reader 1 and from 16 to 25 for reader 2. CONCLUSION: Awareness of clinical data significantly improves reader detection of prostate cancer nodules with endorectal MR imaging and MR spectroscopic imaging, but there is no overall change in reader accuracy, because of an associated increase in false-positive findings. A stricter definition of a true-positive result is associated with reduced sensitivity for prostate cancer nodule detection.