Portal vein anatomy in the dog: comparison between computed tomographic angiography (CTA) and intraoperative mesenteric portovenography (IOMP).

To compare and contrast the findings of intra-operative mesenteric portovenography (IOMP) and computed tomography angiography (CTA) for the visualisation and identification of the extrahepatic and intrahepatic portal venous system in the normal dog. Retrospective study of dogs with raised post-prandial bile acids concentrations, normal portal venous pressures and grossly normal portal vasculature that had undergone both CTA and IOMP was performed. Images and video were compared with the published anatomic literature. Ten dogs met the inclusion criteria. CTA documented the portal vein and its tributaries in all 10 dogs. IOMP documented the portal vein and the cranial mesenteric vein in all 10 dogs and the splenic vein in 1 dog but failed to show the caudal mesenteric and gastroduodenal veins in any dog. CTA documented more extrahepatic portal venous tributaries than IOMP. Both techniques documented the intrahepatic portal vasculature completely with equal clarity. There was a large difference between the ability of the two techniques to delineate the normal portal vasculature; CTA consistently visualised the extrahepatic portal vasculature more completely than the IOMP and, as such, might be considered the modality of choice for imaging the normal portal vasculature in the dog.