The value of helical CT and CT portography in diagnosis of the portal vein tumor thrombosis

Objective:To evaluate the characteristics of portal vein tumor thrombosis on helical CT and CT portogra-phy (CTP). Methods:The pre-and postcontrast helical CT scans were performed in 43 cases with portal vein tumor thrombosis , multiplanar reformation (MPR) and additional CTP was done in 30 cases. After therapy, 15 patients were followed up using CT. Results:The portal vein tumor thrombosis could be clearly demonstrated on axial and MPR images. The direct CT features of the portal vein tumor thrombosis were the enlarged portal vein and intraluminal hypodensity or filling defect,and 23% of tumor thrombosis were heterogeneously enhanced on arterial phase images. The indirect findings included enhancement of vessel wall (42%) .demonstration of collateral circulation formation (100% ),cavernous transformation of the portal vein (44%) and hemodynamic changes in the peripheral hepatic parenchyma. CTP could directly display the location,diameter, degree of the occlusion and the extent of collateral circulation. CT scans could also show the changes of portal vein tumor thrombosis responding to the therapy clearly. Conclusion: Axial helical CT scans, together with the MPR and CTP images,can provide a comprehensive information about the portal vein tumor thrombosis.