ULTRASONOGRAPHY OF PORTOSYSTEMIC SHUNTS IN DOGS AND CATS

Ultrasonography is a rapid, accurate, noninvasive diagnostic test for primary (congenital) and secondary (acquired) portosystemic shunting i n dogs and cats. Two-dimensional, gray-scale ultrasonography alone ena bles diagnosis of most congenital portosystemic shunts and determinati on of intra- versus extrahepatic location. Use of duplex- and color-fl ow Doppler ultrasonography aids detection of congenital and acquired e xtrahepatic portosystemic shunts. The underlying cause of acquired por tosystemic shunting is portal hypertension; this may be documented by finding either hepatofugal or reduced velocity hepatopetal portal bloo d flow by duplex-Doppler. Also, ultrasonography may enable detection o f lesions involved in the pathogenesis of portal hypertension, for exa mple, hepatic arterioportal fistula, hepatic parenchymal lesions, and portal vein thrombosis.