Todani Classification of Choledochal Cysts
classification and cross sectional imaging features of choledochal cysts
Choledochal cysts are congenital cystic dilations of the bile ducts, with the vast majority presenting in childhood, more commonly seen in women than in men. These are divided into 5 subtypes as per the Todani Classification.
The below table details the classification and imaging findings. It is important to recognize, and potentially surgically resect, choledochal cysts, given the increased risk of recurrent ascending cholangitis, calculus formation, and cholangiocarcinoma. In types I through V, focal or multifocal dilation of the bile ducts is seen, sometimes with presence of intraductal calculi. In type V, the “central dot” sign may also be encountered, which appears within the liver as an enhancing portal venous radicle surrounded by dilated bile duct radicles.
Todani Classification of Choledochal Cysts
TYPE | DESCRIPTION | OTHER |
---|---|---|
I(a-c) | Diffuse or segmental fusiform dilation of extrahepatic bile duct | Most common type (80% to 90%) |
II | Saccular bile duct diverticulum | Rare type (2%) |
III | Focal dilation of intramural segment of distal CBD in 2nd portion of duodenum | Also known as a choledochocele, uncommon type (5%) |
IVa | Multifocal dilation of intrahepatic and extrahepatic bile ducts | Second most common type (10%) |
IVb | Multifocal dilation of extrahepatic bile ducts | |
V | Multifocal dilation of intrahepatic bile ducts | Also known as Caroli’s disease, rare type; may be associated with congenital hepatic fibrosis, medullary sponge kidney, and cystic renal disease |