[Importance of biological findings in the ultrasonic diagnosis of neoplastic biliary obstructions].

The authors' purpose is to demonstrate the possibility of improving US reliability in the diagnosis of neoplastic obstructions of the bile ducts, basing their study on the hematic alkaline phosphatase level (AP), which is an earlier sign of obstruction than high bilirubin values. All 368 patients observed had AP levels above the threshold of 270 IU/l. The 34 patients with neoplastic obstruction (including 13 without jaundice) had more than twice the normal level of AP, and presented with at least one dilated bile duct in the biliary tree. Coronal scans of the main bile duct are fundamental in the diagnosis of the level of obstruction. It seems thus possible to affirm that US diagnosis of the biliary obstruction, together with high AP values (more than twice the normal), provides with reliable information as to the neoplastic nature of the biliary obstruction, even if jaundice is not present.