Segmental biliary obstruction: false-negative diagnosis with direct cholangiography without US guidance.

Segmental intrahepatic ductal obstruction with calculi can be a significant cause of acute cholangitis that may remain entirely undetected on a routine, "blind" direct cholangiogram. Ultrasonography (US) or computed tomography can demonstrate isolated intrahepatic ductal dilatation with or without calculi. US, in particular, can be used to direct the needle puncture for percutaneous transhepatic cholangiography (PTC) and thus enable the differential diagnosis and appropriate therapy to be determined. Four cases are reported in which US-guided PTC enabled confirmation of the diagnosis of acute cholangitis secondary to segmental biliary obstruction and intrahepatic calculi. In two the correct diagnosis could not be made with initial blind direct cholangiography, and in the other two, US and US-guided PTC were performed initially.