The portal vein (PV) (sometimes referred to as the main or hepatic portal vein) is the main vessel in the portal venous system and drains blood from the gastrointestinal tract and spleen to the liver. The portal vein usually measures approximately 8 cm in length in adults with a maximum diameter of 13 mm.What is the Normal portal vein velocity?
Normal main portal vein (MPV) peak systolic velocities range between 20 cm/sec and 40 cm/sec. A low flow velocity of <16 cm/sec in addition to a caliber increase in the MPV are diagnostic features of portal hypertension .What is portal vein aneurysm?
Portal vein aneurysm (PVA) is an unusual vascular dilatation of the portal vein, which was firstly described by Barzilai and Kleckner  in 1956 and since then less than 200 cases have been reported in the literature, mainly as case reports or small surgical series.What is portal vein system?
There are two venous systems that drain abdominal structures – the portal venous system and the systemic venous system. The portal system transports venous blood to the liver for processing, whilst the systemic venous system returns blood to the right atrium of the heart.