Portal vein thrombosis in liver cirrhosis - the added value of contrast enhanced ultrasonography.

Portal vein thrombosis (PVT) is a frequent complication of liver cirrhosis and its prevalence increases with the severity of liver disease. Patients with liver cirrhosis and hepatocellular carcinoma may have either malignant or blunt (benign) PVT. In these patients, the diagnosis and characterization of PVT is important for the prognosis and further treatment. Ultrasound (US) is the modality of choice for the diagnosis of PVT. The features of PVT on B-mode (gray-scale) US include: dilatation of the portal vein, visualization of the thrombus and, in chronic PVT- cavernous transformation. Sensitivity of US in the diagnosis of PVT is improved by the use of Doppler US and of ultrasound contrast agents. In the latter years, contrast enhanced ultrasound (CEUS) showed high sensitivity in the differential diagnosis between benign and malignant PVT and could be the diagnostic method of choice for the characterization of PVT. Blunt thrombi are avascular and will not enhance during CEUS examination, while a hyperenhancement pattern of the portal thrombus in the arterial phase, with "wash out" in the portal or late phase is typical for malignant PVT.