Abnormal intraabdominal gas collections visualized on computed tomography: a clinical and experimental study.

Abnormal intraabdominal gas collections visualized on CT scans during a 1-year period were reviewed. There were 34 collections in 29 patients. Sixty-two percent of these abnormalities were noninfectious and iatrogenic in origin, usually a direct result of procedures such as surgery, diagnostic tests, and needle or tube placement. Infections/abscesses (18%), hernias (15%), and gastrointestinal perforations (6%) produced the other abnormal gas collections. In the experimental animal study, gas collections as small as 5cc could be visualized on CT images. Collections of up to 20cc were visible for similar periods of time on both CT scans and conventional radiographs. It is concluded that most abnormally placed gas collections seen on CT are iatrogenic and that CT scans are very sensitive for the detection of such collections.