Sonography of the bile ducts after a fatty meal: an aid in detection of obstruction.

The sonographic response of the biliary tree to a fatty meal was assessed in 78 individuals by measuring common hepatic duct caliber before and after fat ingestion. In the normal cases, the common hepatic duct remained the same or decreased in caliber. Abnormal responses consisted of a normal-caliber duct that increased in size or a slightly dilated duct that remained the same or increased in size. By employing these criteria, we discovered patients with ampullary stenosis, common duct stones, cholangiocarcinoma, and chronic pancreatitis. It is concluded that biliary sonography after ingestion of a fatty meal can aid in the evaluation of a common hepatic duct that is equivocally or mildly dilated and can indicate the need for further invasive studies.