Obstructive jaundice in the absence of sonographic biliary dilatation.

Four patients evaluated for obstructive jaundice had an ultrasonic examination without evidence of biliary dilatation. Subsequent percutaneous transhepatic cholangiographic examinations demonstrated an obstructive etiology without dilatation of the biliary system. Findings in these patients emphasize that the absence of sonographic biliary dilatation does not exclude the diagnosis of obstructive jaundice.