Detection of intestinal ischemia in patients with acute small-bowel obstruction due to adhesions or hernia: Efficacy of CT

OBJECTIVE. The purpose of this study was to determine whether CT can be used to diagnose ischemia of the small intestine in patients with small-bowel obstruction due to adhesions or hernia, SUBJECTS AND METHODS. During a 12-month period, 60 patients underwent surgery for complete or high-grade small-bowel obstruction due to adhesions or hernia, and 29 (48%) had evidence of associated intestinal ischemia. All of these patients had been preoperatively diagnosed by CT as having high-grade small-bower obstruction, At the same time, a prospective determination was made based on the CT studies as to whether there was any associated intestinal ischemia, All CT scans were performed within 24 hours of the operation. A CT diagnosis of ischemia was based on the presence of two or more of the following signs: bower-wall thickening, high attenuation of the bowel wall on unenhanced CT scans, mesenteric edema or fluid, asymmetric bowel-wall enhancement on IV contrast-enhanced CT scans, pneumatosis, or portal venous gas, Results of the CT examination and surgical findings were then compared, Further evaluation was done with a retrospective multivariate discriminant analysis, RESULTS, Ischemia was prospectively diagnosed on the basis of CT findings in 41 (68%) of the 60 patients, There were no false-negative CT diagnoses (sensitivity, 100%); however, there were 12 CT diagnoses that were false-positive (specificity, 61%),The multivariate analysis corroborated the prospective results by showing high sensitivity (90%) and diminished specificity (50-64%), Bowel wall thickening and high attenuation of the bowel wall were the most important signs of ischemia on unenhanced CT scans, whereas abnormal bowel-wall enhancement and mesenteric fluid correlated best on enhanced CT examinations. CONCLUSION, CT is a sensitive but not completely specific preoperative indicator of intestinal ischemia in patients with small-bower obstruction due to hernias or adhesions.