Normal and obstructed main bile duct evaluated by a modified ultrasound technique.

A modified ultrasound technique for demonstration of the extrahepatic bile duct was used in 75 patients and 135 normal subjects. The right and left hepatic ducts, common hepatic duct, and on occasion a part of a dilated cystic duct could be demonstrated with a rate of success of 100 per cent in patients and 98.5 per cent in normal subjects. Usually, the biliary tract can be demonstrated only in part in the conventional supine position, while the modified technique often improved the demonstration of the entire duct and in some cases of a main bile duct that cannot be evaluated in the conventional supine position.