Biliary Duct Dilatation: AJR Expert Panel Narrative Review

Biliary duct dilation is a common incidental finding in practice, but one unlikely to indicate biliary obstruction in the absence of clinical symptoms or elevated liver chemistries. However, the clinical presentation may be nonspecific, and the liver chemistries either unavailable or difficult to interpret. The goal of this article is to review a series of topics fundamental to the management of biliary duct dilation, providing consensus recommendations in a question-and-answer format. We start by covering a basic approach to interpreting liver chemistries, strengths and weaknesses of the biliary imaging modalities, and how and where to measure the extrahepatic bile duct. Next, we define criteria for biliary duct dilation, including patients with prior cholecystectomy and advanced age, and cover when and if biliary duct dilation can be attributed to papillary stenosis or sphincter of Oddi dysfunction. Subsequently, we discuss two conditions in which the duct is pathologically dilated but not obstructed: congenital cystic dilation (i.e., choledochal cyst) and intraductal papillary neoplasm of the bile duct. Finally, we provide guidance on when to recommend obtaining additional imaging or testing such as endoscopic ultrasound or ERCP, and include a discussion of future directions in biliary imaging.