CT imaging of biliary enteric fistula

Abstract.

Background: To define the signs useful for differentiating between gallbladder–enteric fistula (GB-EF) and common bile duct–enteric fistula (CBD-EF) on computed tomography (CT) because the prognosis and management of the two are different.

Methods: CT scans in 13 patients with pneumobilia, who had not had surgical biliary–enteric anastomosis and endoscopic sphincterotomy, were reviewed. The presence of fistula itself, the location of air in the biliary system, and the appearance of the gallbladder were assessed.

Results: The causes of pneumobilia were GB-EF in seven patients, CBD-EF in three patients, emphysematous cholecystitis (EC) in one patient, gallbladder cancer (GBC) in one patient, and incompetent sphincter of Oddi in one patient. In three of seven GB-EF patients (43%) and in none of the three CBD-EF patients (0%), the fistula itself was detected. Air was detected in the common bile duct in four of seven GB-EF (57%) and in all three CBD-EF (100%) patients, and GBC. In six of seven GB-EF (86%) and in one of three CBD-EF (33%) patients, the gallbladder was contracted. Thus, the location of air and the contraction of gallbladder were useful signs to differentiate GB-EF from CBD-EF.

Conclusion: CT can distinguish between GB-EF and CBD-EF.