Differentiation of simple and strangulated small-bowel obstructions: Usefulness of known CT criteria

PURPOSE: To evaluate the usefulness of known computed tomographic (CT) criteria for the differentiation of simple and strangulated small-bowel obstructions. MATERIALS AND METHODS: CT scans of 84 patients with simple (n = 43) and strangulated (n = 41) small bowel obstructions caused by adhesions, hernia, and volvulus were reviewed retrospectively. Diagnoses were made with surgery (n = 55) and during clinical follow-up (n = 29). CT criteria evaluated were configuration of obstructed bowel loop, target sign, bowel wall thickening and enhancement changes in mesentery and mesenteric vasculature, and amount and attenuation of ascites. RESULTS: CT findings that enabled the detection of strangulated obstructions were poor or no enhancement of bowel wall (sensitivity, 34%; specificity, 100%) and a serrated beak (sensitivity, 32%; specificity, 100%). When these two findings were excluded from analysis, a large amount of ascites, an unusual course of mesenteric vasculature, and diffuse engorgement of mesenteric vasculature were shown to be useful CT findings for performing multivariate regression analysis. Application of these five CT findings enabled identification of 35 (85%) of 41 patients with strangulated obstructions. CONCLUSION: Detecting a combination of selected, known CT criteria increases the diagnostic accuracy of CT to enable differentiation of simple and strangulated small-bowel obstructions.