Segmental Bowel Hypoenhancement on CT Predicts Ischemic Mesenteric Laceration After Blunt Trauma

OBJECTIVE. The objectives of this study were to examine the performance of CT in the diagnosis of ischemic mesenteric laceration after blunt trauma and to assess the predictive value of various CT signs for this injury. MATERIALS AND METHODS. In this retrospective study, consecutive patients with bowel and mesenteric injury diagnosed by CT or surgery from January 2011 through December 2016 were analyzed. Two radiologists evaluated CT images for nine signs of bowel injury. The outcome evaluated was ischemic mesenteric laceration. Univariable analysis followed by logistic regression was performed. RESULTS. The study included 147 patients (96 men and 51 women; median age, 35 years; age range, 23-52 years). Thirty-three patients had surgically confirmed ischemic mesenteric lacerations. CT signs that correlated with ischemic mesenteric laceration were abdominal wall injury, mesenteric contusion, free fluid, segmental bowel hypoenhancement, and bowel hyperenhancement adjacent to a hypoenhancing segment. The regression model developed after inclusion of clinical variables identified two predictors: segmental bowel hypoenhancement (adjusted odds ratio, 22.9 [95% CI, 7.9-66.2; p < .001] for reviewer 1 and 20.7 [95% CI, 7.2-59.0; p < .001] for reviewer 2) and abdominal wall injury (adjusted odds ratio, 5.26 [95% CI, 1.7-15.9; p = .003] for reviewer 1 and 5.3 [95% CI, 1.9-15.0; p = .002] for reviewer 2), which yielded an AUC of 0.87 for predicting injury. For reviewer 1 and reviewer 2, the sensitivities of CT in detecting the injury were 72.3% (95% CI, 54.5-86.7%) and 78.8% (95% CI, 61.0-91.0%), respectively, whereas the specificities were 94.7% (95% CI, 88.9-98.0%), and 92.1% (95% CI, 85.5-96.3%), respectively. CONCLUSION. CT has limited sensitivity but good specificity for detecting ischemic mesenteric laceration, with segmental bowel hypoenhancement considered the most predictive imaging sign.