Purpose or Case Report: A pictorial review of imaging appearances of anatomic variations of the portal vein.
Classification and pictorial review of various congenital abnormalities of the portal vein.
Common variations and branching patterns include trifurcation of the main PV, right posterior segmental branch arising from the main PV, and right anterior segmental branch arising from the left PV. Other less common branching patterns include left PV arising from the right anterior segmental branch, duplication of PV and absent branching of PV.
Portal venous shunts may be either portosystemic shunts with abnormal communication between the portal and systemic venous systems or arterioportal shunts between portal venous system and hepatic artery.
Portosystemic shunts bypass the liver and shunt directly portal venous blood into systemic venous system.
Congenital intrahepatic portosystemic shunts are classified into four types based on Park et al. Type I, the most common type, a single vessel connects the right portal vein to the IVC. Type II in which peripheral shunt localized to one hepatic segment and single or multiple communications between branches of portal and hepatic veins. Type III with aneurysmal connection between portal and hepatic veins. Type IV with multiple communications between peripheral portal and hepatic veins in several segments.
Abernethy malformations/congenital extrahepatic portosystemic shunts can be divided into 2 major types. Type I with complete absence of intrahepatic portal venous flow and complete shunting. Type Ia with congenital absence of the portal vein and separate drainage of superior mesenteric vein and splenic vein into systemic veins. Type IIb in which superior mesenteric vein and splenic vein join to form a short extrahepatic portal vein which drains into a systemic vein. Type II with some preserved hepatic portal venous flow and partial shunting. Type IIa arising from left or right portal vein including patent ductus venosus. Type IIb arising from main portal vein. Type IIc arising from the other portal vein tributaries. Patients with both these types suffer premature mortality either due to shunting complications or other associated congenital abnormalities.
Congenital arterioportal shunts may present either as a fistula or as vascular malformations in hereditary hemorrhagic telangiectasia.
Aneurysms of the PV may represent approximately 3% of all aneurysms of the venous system.
Methods & Materials:
Results:
Conclusions: