Intrahepatic portosystemic venous shunts: spectrum of CT findings in external and internal subtypes.

Abstract

The purpose of this work was to survey the spectrum of CT findings in intrahepatic portosystemic venous shunts (IPSVSs). One thousand consecutive liver CT scans examined with an enhanced helical technique were retrospectively reviewed on workstation to find IPSVSs. IPSVSs were noted in 37 patients and divided into two subtypes according to the location of the communicating systemic vein, either outside (external type, n = 34) or within (n = 4) the liver (one patient had both internal and external types). All the external-type shunts were noted in cases with portal hypertension (n = 34). Most shunts (n = 30) ran through segment 4 and/or 3 and came out near the falciform ligament, but five shunts were noted in segment 2 communicating either with the systemic vein (n = 3) or probably with an enlarged left gastric vein (n = 2). Solitary portohepatic venous shunts (internal type) were noted in three cases with (n = 2) or without (n = 1) aneurysmal dilatation and many portohepatic venous shunts in another patient. IPSVSs of the external type were far common than those of the internal type, always associated with increased pressure of the portal system and in specific sites probably lacking the hepatic capsule.