Congenital biliary dilatation: a spectrum of disease detailed by ultrasound.

Recently we have examined six children with the diagnosis of choledochal cyst who demonstrate a greater spectrum of biliary involvement than expected. Classically choledochal cysts have been divided into types and subtypes based on the configuration of common bile duct dilatation; however, this simplified information is misleading since surgical management is dependent on the exact extent of intrahepatic and extrahepatic biliary abnormalities. The pre-operative ultrasound examination must be meticulous to provide enough pertinent anatomic details. Much of the intrahepatic anatomy is not visualized at surgery nor on the operative cholangiograms where reflux of contrast into the intrahepatic ducts may not be consistently achieved.