Radiological findings in biliary fistula and gallstone ileus

Purpose: Biliary fistual and gallstone ileus are rarely found. The diagnosis is difficult and may be delayed until operation. We reviewed the radiological findings in a retrospective material. Material and Methods: The cases of 16 patients treated for biliary fistula were analyzed with respect to findings at imaging. Ten patients had a spontaneous fistula. Nine of them had an internal bilioduodenal fistula and one had an external fistula with stones passing through a subcutaneous abscess. Five patients also had gallstone ileus and one patient a rare gastric outlet obstruction caused by a gallstone (Bouveret's syndrome). Six patients had an iatrogenic fistula. One of them had internal bile ascites and 5 an external fistula, one of which was a biliocystic fistula resulting from attempted hepatic cyst sclerotherapy. Results: Various imaging modalities were used and there was often a delay in the diagnosis. Imaging did not show the fistula itself in any of the spontaneous cases. However, a nonvisualized or shrunken gallbladder seen at US often coexisted in these cases. CT yielded the diagnosis in one case of gallstone ileus, and a Gastrografin metal yielded it in the case of Bouveret's syndrome. Fistulography and cholangiography provided a correct diagnosis of fistula in all cases of iatrogenic biliocutaneous fistulas. Conclusion: Patients with biliary fistula usually undergo examinations with nonspecific results. The imaging findings could be more specific if the possibility of this diagnosis were remembered. (orig.)