The value of dynamic (triphasic) computed tomography in differentiating malignant and benign portal vein thrombi using thrombus density

Background: Portal vein thrombosis (PVT) is the development of thrombus in the main trunk of a portal vein and its intrahepatic right and left branches. Malignant PVT typically arises from invasion of hepatocellular carcinoma into the portal vein of patients with liver cirrhosis. In contrast, bland PVT is attributed to sluggish portal venous flow in cirrhotic patients with portal hypertension. The study was to determine the diagnostic performance of Triphasic CT imaging using thrombus density in differentiating malignant from benignportal vein thrombi.Methods: In this retrospective study, 46 patients with PVT who had contrast-enhanced Triphasic CT of the abdomen were evaluated for PVT. The assessment was performed by measuring the CT attenuation values of the thrombi in Hounsfield Units (HU). ROC (Receiver Operating Characteristic) curves were used to identify accuracy and optimal cutoff values.Results:Out of the 46 CT studies, 32 neoplastic thrombi and 14 bland thrombi were identified on the images. All patients with malignant thrombosis showed contrast enhancement while all patients with bland thrombi demonstrated no contrast enhancement. Contrast enhanced CT showed thrombi density sensitivity of 93.8%, specificity of 100% and accuracy of 95.7%. The AUCs was 0.539 in precontrast and 0.996 in portovenous phase for thrombus density. The optimal cut off in precontrast was 28.5 and in porto-venous phase was 59.0.Conclusion: Estimating thrombi density with triphasic dynamic CT may represent a vital tool for reliable differentiation of neoplastic from bland thrombi in patients with PVT. Key Words: Dynamic CT, Differentiating Benign, Malignant, PVT