Doppler ultrasound in diagnosis of liver tumor and portal hypertension.

Technical aspects (equipment, presetting, enhancement) are considered together with new approaches like interventional radiology and Doppler ultrasound. In liver tumors Doppler US not always shows typical patterns: in hemangioma there is usually poor vascularization, while in malignant tumors the data are: high speed arterial blood flow; turbulent flow in the feeding artery; changes in arterial flow pattern; decreased or reversed flow in the portal branch; arterio-portal or arterio-venous shunts; neovascularization in the tumor; compression, displacement and infiltration of blood vessels. Quantitative measurements by Doppler US in portal hypertension indicate that the cross-sectional area is enlarged and the portal blood flow velocity is decreased. Collateral blood flow usually indicates a turbulent flow. A classification of portal hypertension can be done using Doppler-US, according to the existing site of elevated vascular resistance: pre-sinusoidal, sinusoidal and post-sinusoidal. The first type is represented by extra-hepatic portal vein obstruction. Typical case of second type is cirrhosis of the liver caused by alcoholic or viral hepatitis. Budd-Chiari syndrome is a typical case of the third type.