[CT scanning in suspected ileus or pneumoperitoneum]

In this prospective survey of six months duration, 66 consecutive patients referred for plain abdominal views on suspicion of bowel obstruction or pneumoperitoneum had supplementary abdominal CT-scans performed. Thirty-one patients underwent surgery. Seventeen suffered from bowel obstruction, one patient had both bowel obstruction and pneumoperitoneum and three had pneumoperitoneum. CT-scans correctly demonstrated all cases of bowel obstruction or pneumoperitoneum. The plain abdominal views resulted in one false negative diagnosis of bowel obstruction and one false negative diagnosis of pneumoperitoneum. Ten of the operated patients had neither bowel obstruction nor pneumoperitoneum. In nine of these cases this was in accordance with the interpretation of both CT and plain abdominal views. Both modalities resulted in one false positive diagnosis of bowel obstruction. In most cases we find no difference between the two modalities in demonstrating or excluding bowel obstruction or pneumoperitoneum. We therefore conclude that the plain abdominal X-ray should be the primary examination on suspicion of bowel obstruction or pneumoperitoneum. We recommend CT-scanning in cases with clinical suspicion of bowel obstruction or pneumoperitoneum and no obvious pathology on the plain abdominal X-ray.