[Status of ultrasound diagnosis in differential cholestasis diagnosis]

Differentiating between the hepatocellular "internal" and the "surgical" or "endoscopic" cholestasis syndrome has become a domain of sonography. There is a 92 to 99% success rate, due to the possibility of diagnosing by means of sonography dilations of the gall bladder, the extrahepatic biliary tract and the intrahepatic bile ducts, as well as numerous diseases of the hepatobiliary system and of the pancreas. Congested intra- and extrahepatic bile ducts indicate the presence of a deep-seated distal obstruction, such s a prepapillary concrement, an inflammatory or malignant papillary stenosis or of a process in the area of the head of the pancreas. If the intrahepatic bile ducts alone are dilated the obstructive process has to be assumed near the portal fissure of the liver. Frequent causes are directly demonstrable tumors or metastases on the hilum or high-lying concrements. By using sonography, the level of obstruction can be determined correctly in about 90% of cases, while the cause of obstruction can be diagnosed in about 60 to 70%. In most cases intrahepatic cholestase can only be demonstrated indirectly through the absence of a bile duct dilation. Characteristic diffuse changes in the liver (e.g. fatty liver, cirrhosis, cardiac liver) or intrahepatic space claims-may be in combination with an ultrasound-directed puncture-may support or confirm the diagnosis.