[Echo-Doppler in the study of pre- and post-hepatic portal hypertension]

Portal hypertension is due to a number of pathologic processes; these conditions cause hypertension mostly by hindering the portal flow. The obstacle to portal flow may be located at three different levels--i.e., subhepatic, intrahepatic and suprahepatic. The intrahepatic obstacle is observed in 95% of patients with portal hypertension, while the extra-hepatic causes are rare. This paper is aimed at assessing the diagnostic capabilities of color-Doppler US in the evaluation of pre- and posthepatic portal hypertension. This technique, combining morphologic and Doppler data, allows hypertension to be demonstrated and its degree to be assessed. Color-Doppler US can also define the intra/extrahepatic cause and the level of the obstacle to portal flow. In the diagnosis of the involved processes, the role of color-Doppler US is discussed and compared to the roles of other techniques.