How can you classify choledochal cysts?
Commonly accepted classification currently is one devised by Todani et al. There are five main types, with several subtypes some of which can be pathologically unrelated.
There is fusiform dilatation of the extrahepatic bile ducts (both common hepatic and CBD) containing multiple low signal intensities on all sequences dependently in keeping with stones. No intrahepatic biliary dilatation.
There is a small cystic (high T2, low T1 and no enhancement) in the head of the pancreas with connection to what appears to be a side branch duct, consistent with side branch IPMN. No dilatation of the main pancreatic duct. No evidence of enhancing component.
Interpretation: Choledochal cyst (type 1) with incidental side branch IPMN.