==Procedure==
*Take an initial anteroposterior image including the presumed locations of the gallbladder and common bile duct.
*Infuse Inject iodinated contrast, usually amounting to approximately 5g of iodine (or about 20 ml of concentration 240mg/ml, but can possibly be multiple times more), and note the following:
:*Location of the tip of the drain in relation to the gallbladder
:*Flow into the duodenum, or most distal part reached.