Radiological findings in biliary fistula and gallstone ileus

Biliary fistula 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.

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.

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 meal 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.

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.