Blunt abdominal trauma: Performance of CT without oral contrast material

PURPOSE: To retrospectively evaluate multi - detector row computed tomography (CT) without oral contrast material for depiction of bowel and mesenteric injuries that require surgical repair in patients with blunt abdominal trauma. MATERIALS AND METHODS: The investigational review board approved the study. Informed consent was waived. CT reports for October 2001 to September 2003 were reviewed and 1082 patients were identified who had undergone abdominopelvic CT with a multi - detector row scanner and without oral contrast material. Findings were divided into four categories: negative, solid organ injury with or without hemoperitoneum, free fluid only, and suspected bowel or mesenteric injury. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated by comparing CT findings with laparotomy reports and hospital course. RESULTS: CT findings were no intraabdominal injury ( n = 932), solid organ injury only ( n = 102), free fluid only ( n = 34), and suspected bowel or mesenteric injury ( n = 14). CT findings in patients suspected of having bowel or mesenteric injury were pneumoperitoneum with other secondary findings ( n = 4), mesenteric hematoma and bowel wall abnormality ( n = 2), mesenteric hematoma only ( n = 4), and bowel wall thickening only ( n = 4). In 11 patients, bowel or mesenteric injury was proved surgically. Thus, the study included 1066 true-negative, nine true-positive, two false-negative, and five false-positive results. Based on these data, sensitivity was 82% (95% confidence interval [CI]: 52%, 95%), specificity was 99% ( 95% CI: 98%, 99%), positive predictive value was 64% ( 95% CI: 39%, 83%), and negative predictive value was 99% ( 95% CI: 98%, 99%) for depiction of bowel and mesenteric injuries. CONCLUSION: Multi - detector row CT without oral contrast material is adequate for depiction of bowel and mesenteric injuries that require surgical repair. Results are comparable with previously reported data for single - detector row helical CT with oral contrast material.