Diagnostic accuracy of gray scale ultrasongraphy for the jaundiced patient. A report of 275 cases.

This study of cholestatic jaundice suggests that gray scale ultrasonography should precede invasive techniques or surgery. The failure of ultrasound to demonstrate dilated ducts suggests intrahepatic cholestasis. Display of liver parenchyma by ultrasound provided the correct diagnosis of diffuse liver disease in 61% of the cases. Observation of a dilated biliary tree allowed differentiation between intrahepatic and extrahepatic obstruction, with an accuracy of 96.4%. One false positive (0.7%) occurred, and most false negatives were due to gallstones producing intermittent obstruction owing to a ball-valve effect. Observations of normal biliary canaliculi suggest that physiological distention of intrahepatic biliary vessels does not occur. Long-standing obstruction of biliary tree may result in permanent distention despite surgical relief, predisposing the patient to recurrent ascending cholangitis. This stresses the need for early diagnosis and prompt relief of extrahepatic biliary obstruction.