Value of computed tomography in the diagnosis of the cause of nontraumatic gastrointestinal tract perforation.

OBJECTIVE: To identify computed tomographic features with a high predictive value to differentiate gastroduodenal ulcer perforations from other causes of perforations in patients with a non-traumatic-free pneumoperitoneum.

MATERIALS AND METHODS: Computed tomographic scans of 81 patients with a non-traumatic-free pneumoperitoneum were reviewed for direct visualization of the perforation site and indirect findings of the perforation, including the presence, amount, and localization of air and ascites in the peritoneal cavity, mural thickness of the gastrointestinal tract, perigastrointestinal fat stranding, intestinal ischemia, fecal peritonitis, abscess, and portomesenteric venous gas.

RESULTS: The perforation site was directly visualized in 16 (41%) of 39 patients with gastroduodenal ulcer perforation and in 5 (12%) of 42 patients with other causes of perforation. The findings with a positive predictive value of more than 90% for gastroduodenal ulcer perforation were the presence of local fluid between the duodenum and the pancreatic head and the combination of local gastroduodenal wall thickening and fat stranding. The presence of abscess in the peritoneal cavity or fecal peritonitis, portomesenteric gas, or bowel ischemia findings had a positive predictive value of 100% for the diagnosis of other perforations.

CONCLUSIONS: Indirect computed tomographic findings are helpful for differentiating gastroduodenal ulcer perforation from other causes of perforations.