Multi-detector CT of blunt mesenteric injuries: usefulness of imaging findings for predicting surgically significant bowel injuries

The objective of this study is to determine which imaging features of blunt mesenteric injuries best predict the presence of a bowel injury requiring surgical correction. The radiology archives at a Level 1 trauma center were searched over a 5-year period to identify patients with mesenteric injuries seen on admission 64 slice MDCT. Two emergency radiologists, blinded to clinical and surgical outcomes, retrospectively recorded mesenteric injury size, the presence/absence of active mesenteric bleeding, bowel wall thickening, adjacent interloop free fluid, extraluminal gas, mesenteric vessel termination, mesenteric vessel "beading", focal bowel wall defect, and bowel wall perfusion abnormality. Based on all of the imaging findings, the radiologists were asked to determine if they thought the patient had a surgical bowel injury. One hundred twenty-six patients with mesenteric injuries were identified. Eighteen patients underwent laparotomy confirming the presence of bowel injury in 15. The remaining patients were successfully managed non-operatively. There was no statistically significant difference in size of mesenteric injury for surgical vs. non-surgical bowel injuries. Active bleeding, adjacent interloop free fluid, and bowel wall perfusion defects were strong predictors of the presence of a surgically significant bowel injury (p < 0.001, 0.002, and 0.020, respectively). The overall accuracy, sensitivity, specificity, PPV, and NPV of 64-MDCT were 73.8%, 80%, 73.0%, 28.6%, and 96.4%, respectively. Mesenteric active bleeding, adjacent interloop free fluid and bowel wall perfusion defects are associated with surgically significant bowel injuries. The diagnosis of surgical bowel injuries remains challenging despite 64-slice MDCT technology.