Contrast-enhanced multiphasic computed tomography for identifying life-threatening mesenteric hemorrhage and transmural bowel injuries

BACKGROUND:: Active mesenteric hemorrhage and bowel perforation after blunt abdominal trauma warrant immediate surgical intervention. We investigate whether findings on multiphasic computed tomography (CT) can identify life-threatening mesenteric hemorrhage and bowel injuries. METHODS:: Within 1-year period, 106 patients underwent multiphasic CT for evaluation of blunt abdominal injuries. Images obtained at arterial phase, portal phase, and equilibrium phase were retrospectively reviewed with special focus on mesentery and bowel injuries. We compared the recorded findings with surgically proven active mesenteric hemorrhage and transmural bowel injuries. The diagnostic values and positive likelihood ratios of individual CT signs were calculated. RESULTS:: Mesenteric contrast extravasation had 73.5 positive likelihood ratio and 75% sensitivity for active mesenteric hemorrhage. Hemorrhage first appeared at arterial phase and portal phase was active and life threatening, different from a contained hemorrhage appeared only at equilibrium phase. For transmural bowel injuries, positive likelihood ratio of full-thickness bowel wall abnormality and extraluminal air was large at 32.5 and 26.9, respectively. However, increased mesenteric fat density and peritoneal fluid had high negative predictive value at 98.9 and 97.8. Mean radiodensity of peritoneal fluid in transmural bowel injuries was significantly lower (30 vs. 44 Hounsfield unit, p = 0.008). CONCLUSIONS:: Multiphasic CT is accurate in identifying life-threatening mesenteric hemorrhage and transmural bowel injuries.