The role of multi-slice CT in portal vein thrombosis

Objective To discuss the imaging features of portal vein system thrombosis and its secondary changes in multi-slice CT examination.Methods By contrast with the CT features of tumor thrombus in portal vein system in 50 cases which confirmed by histopathology,we retrospectively analyzed the dynamic enhancement CT features of venous thrombosis in portal vein system and its secondary changes in 37 consecutive patients,who were diagnosed by histopathology or clinic data combined with imaging follow-up more than 6 months.Results Except for chronic organized thrombus in 3 cases,in all the other 34 cases,benign thrombus in portal vein system(34/37,91.89%) had smooth edge,clear border and regular contour.The related portal wall presented distinct linear enhancement in those cases.While in tumor thrombus group,we couldn't found linear enhancement on the related portal wall.In contrast-enhanced hepatic arterial phase the mean enhancement of these 34 benign thrombus was(9.32±5.32) Hu,which had a significant difference from that of tumor thrombus([43.08±14.05] Hu)(t=15.59,P0.01).In hepatic arterial phase,none of benign thrombus presented enhanced vessel branches;while enhanced nutrient arterial branches could be found in 19 tumor thrombus(19/50,38.00%).Besides these,tumor thrombus was incident to cause complete block(100% in tumor thrombus,32.43% in benign thrombus) and significant dilatation of portal vein(68.00% in tumor thrombus,8.11% in benign thrombus).The secondary changes of portal vein system thrombosis included hepatic parenchyma ischemia in 4 cases,abnormal hepatic perfusion in 14 cases,cavernous transformation of portal vein in 7 cases,acute congestive edema and necrosis of intestinal wall in 3 cases and splenic congestive injury in 4 cases.9 patients with thrombosis in the main trunk of portal vein presented hyper-perfusion areas in the peripheral part of liver in hepatic arterial phase(9/10);the other one had hyper-perfusion in the whole liver.While all the patients with thrombosis in portal vein branches(4/4) had hyper-perfusion areas in the involved lobe or segment.Conclusion The imaging features of benign thrombosis in portal vein system in multi-slice CT exam are of characteristic,which differentiate from tumor thrombus.And the secondary changes could be estimated in CT exam.So we believe multislice CT examination could supply useful information in guiding clinical treatment for portal vein system thrombosis.