Shotgun Sign

An ultrasonographic sign that can be used to differentiate obstructive jaundice—in which there is biliary dilatation, caused by impacted gallstones in the common bile duct or at the ampulla, benign strictures, pancreatic carcinoma, cholangitis, biliary surgery, and chronic pancreatitis—and non-ostructive jaundice. The name obtains from an appearance fancifully likened to a double-barrelled shot gun in which a dilated common bile duct (not normally seen) is parallel to the portal vein (normally visible)