Ultrasound demonstration of anicteric dilatation of the biliary tree

This report presents eight patients with dilatation of the biliary tree, six of whom had no clinical or laboratory evidence of biliary tract disease except for elevated levels of serum alkaline phosphatase. In two patients, dilatation was caused by obstruction of only one hepatic duct; in three, it was caused by a pancreatic tumor; and in three, it was associated with gallstones which exercised a ball-valve effect, producing intermittent obstruction. The elevation of the alkaline phosphatase level in six of these patients suggests that it is a more sensitive indicator of biliary tract obstruction than the serum bilirubin level is. The recognition of biliary dilatation in one or both lobes of the liver should lead to a careful examination, with ultrasound or another modality, of the porta hepatis, common bile duct, and pancreas.