Endoscopic classification of biliary atresia

Classification of biliary atresia according to appearance on ERCP. In ERCP type 1, present in approximately 30% of patients, there is no visualization of the entire biliary tree. In ERCP type 2, present in approximately 50% of patients, there is visualization of the common bile duct and gallbladder but not of the hepatic duct. In ERCP type 3, present in approximately 20% of patients, there is visualization of the common bile duct and gallbladder, with visualization of biliary lakes at the porta hepatis (type 3a) or of both hepatic ducts (type 3b). Improper positioning of the catheter during ERCP can lead to misclassification. Note that this ERCP classification of biliary atresia is different from the Kasai classification of biliary atresia, which is based on anatomy at operation.