Ultrasonographic spectrum of choledochal cysts in children.

Four different sonographic patterns which may be encountered in choledochal cyst are described. The most common form is concentric dilatation of the common bile duct (Type I). Rarely eccentric dilatation of the common bile duct, diverticulum, may be seen (Type II). Both forms of the disease may (Types IB and IIB) or may not (Types IA and IIA) be asso"iated with intrahepatic biliary dilatation.