[Diagnosis of gallstone ileus]

Gallstone ileus is a rare disorder, which, because it is often misdiagnosed preoperatively, may become life-threatening. The classic triad of Rigler (aerobilia, small bowel ileus and a calcified, dystopic stone) is visualized on abdominal plain films in only 14-35% of cases. Further work-up includes ultrasound, upper gastrointestinal series with water soluble contrast medium and computed tomography (CT). CT is especially reliable in demonstrating all three criteria.