Comparison of Ischemic and Nonischemic Bowel Segments in Patients With Mesenteric Ischemia: Multidetector Row Computed Tomography Findings and Measurement of Bowel Wall Attenuation Changes

Abstract

ObjectiveTo describe multidetector row computed tomography (MDCT) findings and to compare the enhancing ratio of ischemic and nonischemic bowel wall segments in patients with mesenteric ischemia. Patients and MethodsWe performed a retrospective review of 69 patients with pathologically proven mesenteric ischemia who underwent a preoperative MDCT evaluation from January 1, 2010, through December 31, 2014. Two reviewers performed quantitative MDCT measurements of the bowel wall attenuation of the ischemic and nonischemic bowel segments on the unenhanced phase, arterial phase, and portal venous phase. Receiver operating characteristic curves for the enhancing ratios on the arterial phase and portal venous phase (ERv) were calculated to discriminate the 2 segments. A concordance correlation coefficient was used to assess interobserver variability. ResultsThe most common origin of ischemia was the mesenteric artery (45 of the 69 patients [65.2%]), but only 5 patients (7.2%) had evidence of arterial thrombus on MDCT. The quantitative MDCT measurements indicated that the ischemic bowel segments had significantly less bowel wall attenuation than the nonischemic bowel segments on the arterial phase (28.58±9.28 vs 58.97±12.50; P<.001) and the portal venous phase (33.93±11.16 vs 76.25±13.56; P<.001). The enhancing ratio on the arterial phase (cutoff, 0.32 or less; sensitivity, 89.9%; specificity, 98.6%) and the ERv (cutoff, 0.81 or less; sensitivity, 95.7%; specificity, 98.6%) predicted bowel ischemia. The most common MDCT findings in ischemic bowel were thickened bowel wall in 59 patients (85.5%), mesenteric fatty stranding in 57 (82.6%), and decreased bowel wall enhancement in 56 (81.2%). All quantitative measurements reached moderate to substantial agreement (0.399-0.601). ConclusionWithout oral contrast administration and at a constant 120-peak kilovolt setting, MDCT findings of decreased enhancement of the thickened bowel wall together with a low ERv value predicted the presence of an ischemic bowel segment.