Diagnosis of bowel obstruction on plain abdominal radiographs: significance of air-fluid levels at different heights in the same loop of bowel.

Abstract

The presence of differential air-fluid levels is an insensitive method of determining if a bowel obstruction is mechanical, because only a small proportion of mechanical obstructions have differential air-fluid levels. In our population of patients, however, a differential air-fluid level of 20 mm or greater was moderately suggestive that a bowel obstruction was mechanical in nature.