A comparison of computed tomography and sonography in choledocholithiasis.

A comparison was made of sonography and computed tomography (CT) for the diagnosis of choledocholithiasis. Sonography correctly diagnosed nine of 49 patients with choledocholithiasis for a sensitivity rate of 18%. The accuracy rate for sonography was 19%; there were five false-positive examinations. CT correctly identified common duct stones in 26 of 30 patients for a sensitivity rate of 87%. The accuracy rate was 84%; there was one false positive. Sonography is limited in its ability to image calculi in the distal common bile duct. CT is effective for imaging common duct stones and is superior to sonography for diagnosing this cause of biliary obstruction.