Comparison between the site of multislice CT signs of gastrointestinal perforation and the site of perforation detected at surgery in forty perforated patients.

PURPOSE: To compare the site of multislice spiral computed tomography (MSCT) signs of gastrointestinal perforation and the site of perforation at surgery in forty perforated patients.
MATERIALS AND METHODS: Between January 1 and July 31, 2003, a total of 40 patients (23 men and 17 women) underwent surgery for gastrointestinal perforation. In all cases, plain radiography of the abdomen was integrated by MSCT with the following parameters: 0.5 seconds gantry rotation time, 2.5-5.0 mm slice thickness, 3.75 reconstruction interval, 120 kV, 250-300 mAs, pitch 1.5, after intravenous administration of 140 ml of contrast agent at 3 ml/s with an automatic injector and a delay time of 70 seconds from the injection of the contrast agent. The MSCT findings were: free air and free fluid observed in supramesocolic compartments and/or in inframesocolic compartments and bowel wall discontinuity. The sites of the MSCT findings were compared with the site of perforation observed at surgery.
RESULTS: Free air was detected in 60%, free intraperitoneal fluid in 92.5%, and a combination of both findings in 57.5% of the 40 cases examined. There were no cases of bowel wall discontinuity. In nine patients with gastroduodenal perforation, free air and free fluid were detected in combination and free air was localised in supramesocolic compartments in all cases; in two patients with jejunal perforation, free intraperitoneal fluid was observed both in supramesocolic and inframesocolic compartments; in six patients with acute perforated appendicitis, free air was never detected, while free fluid was observed in all cases in inframesocolic compartments; in six patients with isolated sigmoid perforation free air was observed in four cases in supramesocolic compartments while free fluid was seen in both supramesocolic and inframesocolic compartments.
CONCLUSIONS: MSTC is the most reliable diagnostic method with which to assess gastrointestinal perforation as it allows detection of even small amounts of free air in the abdomen, which are a sign of perforation. In our study, the comparison of the sites of MSCT signs of perforation with those observed at surgery showed that in gastroduodenal perforations free air and free fluid are present in combination and free air is localised in supramesocolic compartments; in acute perforated appendicitis free air is absent, while free fluid is present in inframesocolic compartments; in isolated sigmoid perforations free air, if present, is localised in supramesocolic compartments, while free fluid is seen in both compartments.