Portosystemic shunts can be congenital in dogs and cats or the result of sustained portal hypertension. They can greatly vary in morphology, with different origin and termination.
Ultrasound is a useful modality to detect direct and indirect signs of portosystemic shunting. The main features of congenital extrahepatic portosystemic shunts are discussed in this video.
For more infomation, consult pages 224-234 of the Atlas of Small Animal Ultrasonography (2nd edition). The reader is also encouraged to review the normal anatomy of the portal system with 3D images in The Liver
[annotated video without sound, 3:31]
