[Critical evaluation of echography in the diagnosis of cholestatic jaundice]

Seventy one patients affected by cholestasis and jaundice were studied by means of ultrasound between september 1980 and february 1983 in order to evaluate the accuracy of this procedure in the investigation of the site of obstruction and its ethiology. The ultrasound findings were correlated with those obtained by opacification of the bile ducts, either endoscopic or percutaneous, and by surgery. The sonographic diagnosis of cholestatic jaundice was based on the size of the biliary tract taking in account that the intrahepatic branches are not evident in normal conditions and considering 4-5 mm and 7-8 mm as the upper limits for the proximal and distal segments of the common bile duct respectively. The accuracy of ultrasound in establishing the common bile duct size was 98%. Forty eight patients had extrahepatic obstruction, 45 of whom had a dilated common bile duct (94%), while 3 were normal (6%). Twenty two patients had an intrahepatic cholestasis, 20 of whom had a normal size of the common bile duct (91%) while 2 showed a dilatation (9%). Thus, the sensitivity was 95.7% and the specificity 86.9%. The ethiologic diagnosis was available in 31 patients with extrahepatic obstruction (65%) and in 7 with intrahepatic cholestasis (32%). Dilated common bile duct with stones and pancreas and gallbladder carcinoma were the most common causes of obstructions we have found in this group of patients. In patients with cholestasis and jaundice the ultrasonic diagnosis should establish the site of obstruction and, if it is possible, the ethiology.