Rupture of the bowel after blunt abdominal trauma: diagnosis with CT

The accuracy of CT in the detection of injuries of the solid viscera after blunt trauma is well established, but the value of CT in diagnosing bowel rupture resulting from blunt trauma is controversial. This study was conducted to determine the sensitivity of CT in diagnosing posttraumatic bowel rupture.

During a 51-month period, 17 preoperative CT scans were obtained in 16 patients who subsequently had bowel ruptures verified surgically. Both preoperative (prospective) and retrospective CT findings were analyzed in these patients. Retrospective interpretation was made by consensus of two radiologists.

Surgically confirmed bowel ruptures occurred in the duodenum (five), ileum (four), jejunum (four), colon (four), and stomach (two). CT findings considered diagnostic of bowel perforation were detected prospectively on 10 (59%) of 17 scans; these included pneumoperitoneum without prior peritoneal lavage (six), mesenteric, intramural, or retroperitoneal free air (six), or direct visualization of discontinuity of the bowel wall or extravasation of luminal contents (four). Prospective CT findings considered suggestive of bowel rupture were present on five (29%) of the 17 scans; these included intraperitoneal fluid of unknown source (three), thickened (> 4-5 mm) bowel wall (two), gross anterior pararenal fluid without a recognized source (one), and a mesenteric-bowel wall hematoma (one). On two of 17 scans, findings were seen in retrospect only; these included free intraperitoneal blood without a source (findings on a second CT scan were diagnostic) and pneumoperitoneum. CT findings diagnostic or suggestive of bowel injury were detected prospectively on 15 (88%) of 17 scans and were noted in all retrospectively.

CT is sensitive for the diagnosis of bowel rupture resulting from blunt trauma, but careful inspection and technique are required to detect often subtle findings.