Assessment of Strangulation in Adhesive Small Bowel Obstruction on the Basis of Combined CT Findings: Implications for Clinical Care.

Abstract

Purpose To determine which computed tomography (CT) findings or combinations of findings can help to accurately identify strangulation in adhesive small bowel obstruction (SBO). Materials and Methods Contrast agent-enhanced CT findings in a cohort of 256 patients consecutively admitted for adhesive SBO, with a delay of less than 24 hours between CT and surgery for the operated patients, were reviewed independently by two radiologists, with consensus by a third, to assess CT findings commonly associated with strangulation. The reference standard for strangulation was surgery. Univariate and multivariate analyses were performed to identify predictors of strangulation in the entire cohort and to identify predictors of the need for surgical resection in the subgroup of patients with strangulation. A CT score was obtained and diagnostic performances of different combined CT findings were calculated. Results In this study, 105 patients (41.0%; 105 of 256) underwent a surgical procedure, 62 of whom were found to have strangulation (59.0%; 62 of 105), whereas 151 patients (59.0%; 151 of 256) improved with medical care. Three CT findings were significantly associated with strangulation in the multivariate analysis: reduced bowel wall enhancement (odds ratio, 7.8; 95% confidence interval [CI]: 2.6, 23.5), diffuse mesenteric haziness (odds ratio, 6.1; 95% CI: 2.5, 15.2), and a closed-loop mechanism (odds ratio, 6.5; 95% CI: 2.8, 15.5). The model combining these three features had an area under the curve of 0.91 (95% CI: 0.86, 0.96) and a high negative predictive value (97%; 95% CI: 93%, 99%). Positive likelihood ratios were high when two or three of these CT findings were combined (positive likelihood ratios, 14.7 [95% CI: 7.1, 30.4] and 43.8 (95% CI: 14.2, 135.2], respectively). Among the strangulated cases, reduced bowel wall enhancement (odds ratio, 3.9; 95% CI: 1.3, 12) and mesenteric fluid (odds ratio, 3.6; 95% CI: 1.0, 12.8) were predictive of resection. Conclusion A score that combines three CT findings (reduced bowel wall enhancement, a closed-loop mechanism, and diffuse mesenteric haziness) can accurately predict strangulation in adhesive SBO. © RSNA, 2017 Online supplemental material is available for this article.