Why not it is hepatic artery?

why not it is hepatic artery?

This is a color doppler image - so the colour does not tell us Artery or vein - but it is showing us the direction of flow. Usually Red means towards the USG probe so below-to-top - so towards the liver in this case. Blue means away from the probe so to-to-bottom - sou would mean away from the liver. Here this is a blood vessel at the porta hepatis - carrying blood towards the liver - can be both Hepatic artery or Portal vein. Why is it Portal vein ? Because of these 2 vessels - most of the normal liver is supplied by Portal vein - major source of blood supply… A small contribuation comes from the hep artery. Hence at the porta hepatis - Portal vein is very wide(as in this case) whereas Hep artery is usually a very small vessel. So to conclude - this is a wide bore vessel carrying blood into the liver at the porta hepatis - so what is it - Its the Portal vein !

Tortousness of the Vessel can be attributed to the Thckness of the Flow , making it a portal vein

thanks sir