Use of CCK cholescintigraphy to differentiate choledochal cyst from gallbladder.

A 17-year-old girl presented with right upper quadrant pain and was found to have a subhepatic cyst by ultrasound and CT. A DISIDA scan showed prompt filling of both the gallbladder and a very dilated common bile duct consistent with a choledochal cyst. Following intravenous administration of cholecystokinin, there was immediate emptying of the gallbladder into the cyst. Quantitative cholecystokinin cholescintigraphy may be a useful adjunct in the differentiation of choledochal cyst from gallbladder activity.