Choledocholithiasis is a common problem seen in as many as 6-12% of patients undergoing chole-cystectomy. Common bile duct stones may be asymptomatic but can often lead to biliary colic, cholangitis, jaundice, or pancreatitis. In patients in whom Choledocholithiasis is highly suspected, transabdominal sonography is the most commonly used initial examination to screen for gallbladder disease because of its low cost and high accuracy. However, in patients with symptoms that are not specific, such as abdominal pain, or with symptoms that are suspicious for pancreaticocholedochal disease, helical CT performed with IV contrast material is widely used for the initial evaluation. Consequently, radiologists need to recognize the imaging findings of common bile duct stones on contrast-enhanced CT scans because that is often the first opportunity they have to diagnose a common bile duct stone.
Although endoscopic retrograde cholan-giopancreatography (ERCP), MR cholangio-pancreatography, and endoscopic sonography are more sensitive than CT, these modalities are usually not the first imaging tests performed for evaluating common bile duct stones. In this pictorial essay, we illustrate the findings of Choledocholithiasis on contrast-enhanced helical CT and compare them with findings on ERCP.