Accuracy of computed tomography in the screening of obstructive jaundice.

Percutaneous transhepatic cholangiography (PTC) has come back into greater use thanks to Chiba's needle. PTC, however, is useful only in obstructive jaundice (OJ). Since in OJ the dilatation of the intrahepatic biliary tract (IHBTD) is constant, the authors discussed CTs reliability in evaluating IHBTD in a series of 33 patients with OJ studied with PTC. The threshold of CT diagnosis of IHBTD was found to be equal to a doubled caliber of the normal biliary tract. This value is reached by 85% of the patients 2 weeks after the onset of OJ and in 98% between 2 and 3 weeks. CT is therefore usable as a screening method of PTC, as long as it is not performed before 2 weeks after the onset of OJ. After 2 weeks, if CT does not reveal IHBTD, it is possible to exclude OJ.