Sensitivity and Specificity of CT and Its signs for Diagnosis of Strangulation in Patients with Acute Small Bowel Obstruction.

Introduction: To perform a meta-analysis to review the sensitivity and specificity of computed tomography and different known CT signs for the diagnosis of strangulation in patients with acute SBO. Methods:  Pubmed search was performed for all reports that evaluated the use of CT and discussed different CT criteria for the diagnosis of acute SBO. Only articles published in English language between January 1978 to June 2008 were included. The bivariate random effect model was used to obtain pooled sensitivity and pooled specificity. Summary receiver operating curve was calculated using Meta-Disc. Software Openbugs 3.0.3 was used to summarize the data. Results: A total of 12 studies fulfilled the inclusion criteria. The pooled sensitivity and specificity of CT in the diagnosis of strangulation was 0.720 (95% CI 0.674 to 0.763) and 0.866 (95% CI 0.837 to 0.892) respectively. The ranges to pooled sensivity and pooled specificity of different CT signs are 0.309 - 0.623 and 0.717 - 0.991 respectively. Conclusions: This review demonstrates that the sensitivity and specificity of CT is high in preoperative diagnosis of strangulation in the setting of acute SBO which are in accordance with the published studies. Our analysis shows that “presence of mesenteric fluid” is the more sensitive, and “lack of bowel wall enhancement” is the more specific CT sign of strangulation, and also justifies need of large scale prospective studies to validate the results obtained as well as to determine a clinical protocol.