Figure 7a.  Single, small common bile duct calculus and gallbladder calculi in an 18-year-old woman with chronic right upper quadrant pain. (a) Scout MR cholangiogram shows a 3-mm calculus (straight arrow) in the normal-caliber distal common bile duct. The gallbladder (curved arrow) is filled with multiple small calculi. (b) Endoscopic retrograde cholangiopancreatogram helps confirm the distal common bile duct calculus (arrow).