Portal Vein Thrombosis: Imaging the Spectrum of Disease With an Emphasis on MRI Features

OBJECTIVE: The purpose of this article is to review the classic and uncommon imaging findings of portal vein thrombosis (PVT) (acute, chronic, congenital, and septic thrombus) as visualized on multiple modalities, with an emphasis on MRI findings. Additional aims are to understand the imaging of obliterative portal venopathy and its clinical significance, appreciate morphologic changes of the biliary system that may accompany PVT, and recognize changes in liver enhancement patterns seen with PVT related to the hepatic arterial buffer response. The review also addresses morphologic changes of the liver that may occur after PVT, including nodular regenerative hyperplasia, central hepatic hypertrophy, and peripheral fibrosis that may stimulate cirrhosis, as well as the importance of portal vein mapping and the diagnostic findings and clinical significance of tumor within the portal vein in the liver transplant population. CONCLUSION: PVT may be a complication of liver cirrhosis, but it may also occur as a primary vascular disorder without liver disease. PVT can result in portal hypertension and may present with variceal bleeding or hypersplenism. Radiologists should be familiar with the imaging of PVT in patients of various ages and in different clinical scenarios. PVT can influence hepatic perfusion, the shape of the bile ducts, and liver architecture. Bland PVT and tumor-related PVT have major implications for hepatic transplant.