Computerized tomography as an indicator of isolated mesenteric injury. A comparison with peritoneal lavage. This study evaluated 18 patients with blunt abdominal trauma who suffered isolated mesenteric injuries, diagnosed at exploratory laparotomy. Thirteen had diagnostic peritoneal lavage (PL) as their initial diagnostic study, and five had computed tomography (CT). All patients who had positive PL were explored emergently, undergoing repair of mesenteric injuries. Three of the five patients with CT as initial studies had delayed recognition of their injuries due to incorrect initial interpretation of the scan in two, and a false negative scan in one. Two of these patients developed intestinal infarction and required bowel resection. There were no complications in the PL group related to surgery; morbidity was greater in those undergoing CT. We conclude that early laparotomy and repair of significant mesenteric injuries is necessary to reduce morbidity, and that PL is a more sensitive indicator of this injury than CT. 