BENIGN AND MALIGNANT PORTAL-VEIN THROMBOSIS - DIFFERENTIATION BY CT CHARACTERISTICS

OBJECTIVE. The purpose of this study was to determine if unique charac teristics revealed by CT can allow radiologists to reliably distinguis h benign from malignant portal vein thrombus (PVT) in patients with ci rrhosis. MATERIALS AND METHODS. CT examinations of 58 patients with ci rrhosis and PVT were retrospectively reviewed. Images were assessed fo r location, extent, enhancement, neovascularity, and maximal diameter of PVT. The type of PVT was proven histologically in 42 patients and c linically in the remaining 16 patients. Using different threshold PVT diameters or the presence of PVT neovascularity, we calculated the sen sitivity and specificity of CT for revealing malignant PVT. RESULTS. F orty-seven patients had malignant and 11 patients had benign PVT. CT s cans of patients with malignant PVT showed direct extension of hepatoc ellular carcinoma into the portal vein in 15 patients. In 29 patients with malignant PVT, CT scans showed PVT adjacent to tumor; CT scans sh owed tumor PVT remote from hepatocellular carcinoma in the remaining t hree patients with malignant PVT. The mean diameters of malignant and benign portal vein thrombi were significantly different (23.4 mm versu s 16 mm; p =.0001). CT scans of 83% (39/47) of patients with malignant PVT and 18% (2/11) of patients with benign PVT showed generalized enh ancement. Neovascularity was seen on CT scans in 43% (20/47) of patien ts with malignant PVT and in no patient with benign PVT. Identificatio n of a main PVT diameter greater than or equal to 23 mm or PVT neovasc ularity resulted in a sensitivity and specificity for the CT character ization of malignant PVT of 86% and 100%, respectively. CONCLUSION. Ma lignant and benign thrombi can often be differentiated by radiologists on the basis of CT imaging characteristics.