Gray-scale ultrasound of billary tract disease. A correlative study with percutaneous transhepatic cholangiography.

Gray-scale ultrasound can be useful in the diagnosis of extrahepatic obstructive jaundice by the demonstration of dilatation of the biliary tree. The present study was undertaken to test the specificity and sensitivity of gray-scale ultrasound (US) in the detection of dilation of intrahepatic bile ducts, as compared to percutaneous transhepatic cholangiography (PTC). Forty-seven patients were studied prospectively by both techniques. In 23 patients demonstrated by PTC to have dilated intrahepatic ducts, 18 were detected by US. Of the 11 patients shown to have non-dilated ducts by PTC, all were accurately predicted by US. In 13 cases in which PTC was unsuccessful, the US study showed 12 to be non-dilated and one to be mildly dilated. Ultrasound as a non-invasive technique, should be the primary imaging technique in the evaluation of possible extrahepatic obstructive jaundice.