Gallstone ileus analysis of radiological findings in 27 patients.

Purpose: We retrospectively compared the clinical value of plain abdominal film, abdominal sonography and abdominal CT in diagnosing gallstone ileus in 27 patients.
Material and Methods: 27 patients (23 women and 4 men, age range 58-96 years; mean age 71.5 years) with surgically proven gallstone ileus were submitted to plain film, sonography and CT of the abdomen. Abdominal plain films were performed in 19 cases in upright position (postero-anterior projection), in eight cases in supine position. Abdominal US were performed with 3.5 and/or 7.5 MHz probes. CT was performed with a helical unit (slice thickness 4mm, reconstruction interval 4mm, pitch 1.5), after intravenous contrast agent (120 ml) infusion (3 ml/s, 55 s acquisition delay from bolus starting) and using a power injector. The following findings were searched on: pneumobilia, air in gallbladder, cholecysto-digestive fistula, extraluminal fluid, bowel loops dilatation, intestinal air-fluid levels, ectopic stones.
Results: Plain abdominal films showed the following findings: air-fluid levels (77.78% of cases), bowel loops dilatation (88.89%), site of obstruction (44.4%), pneumobilia (37.04%), air in gallbladder (3.70%), ectopic stone (33.33%). Abdominal sonography demonstrated bowel loops dilatation (44.44%), extraluminal fluid (14.81%), ectopic stones (14.81%), gallbladder abnormalities, (37.04%), pneumobilia (55.56%). CT findings retrospectively observed were: bowel loops dilatation (92.59%), air-fluid levels (37.04%), bilio-digestive fistula (14.81%), pneumobilia (88.89%), ectopic stone (81.48%), extraluminal fluid (22.22%). The Rigler's triad, that is pneumobilia, bowel mechanical obstruction and ectopic stone detection was observed 4 times with RX (14.81%), 3 times with US (11.11%) and 21 times with CT (77.78%).
Conclusions: Air-fluid levels and bowel loop dilatation were the radiological findings more frequently observed in our series. Plain abdominal film allowed us mainly to identify signs of obstruction, US were more effective in disclosing biliary pathology, CT allowed us to correctly diagnose biliary ileus with much higher accuracy.