Diagnosis of benign and malignant portal vein thrombosis in cirrhotic patients with hepatocellular carcinoma: color Doppler US, contrast-enhanced US, and fine-needle biopsy

Background We assessed the role of contrast-enhanced ultrasound (CEUS) in the differential diagnosis between benign and malignant portal vein thrombosis in patients who had cirrhosis with hepatocellular carcinoma (HCC). Methods Fifty-four consecutive patients who had cirrhosis, biopsy-proved HCC, and thrombosis of the main portal vein and/or left/right portal vein on US were prospectively studied with color Doppler US (CDUS) and CEUS. CEUS was performed at low mechanical index after intravenous administration of a second-generation contrast agent (SonoVue, Bracco, Milan, Italy). Presence or absence of CDUS signals or thrombus enhancement on CEUS were considered diagnostic for malignant or benign portal vein thrombosis. Twenty-eight patients also underwent percutaneous portal vein fine-needle biopsy (FNB) under US guidance. All patients were followed-up bimonthly by CDUS. Shrinkage of the thrombus and/or recanalization of the vessels on CDUS during follow-up were considered definitive evidence of the benign nature of the thrombosis, whereas enlargement of the thrombus, disruption of the vessel wall, and parenchymal infiltration over follow-up were considered consistent with malignancy. CDUS, CEUS, and FNB results were compared with those at follow-up. Results Follow-up (4 to 21 months) showed signs of malignant thrombosis in 34 of 54 patients. FNB produced a true-positive result for malignancy in 19 of 25 patients, a false-negative result in six of 25 patients, and a true-negative result in three of three patients. CDUS was positive in seven of 54 patients. CEUS showed enhancement of the thrombus in 30 of 54 patients. No false-positive result was observed at CDUS, CEUS, and FNB. Sensitivities of CDUS, CEUS, and FNB in detecting malignant thrombi were 20%, 88%, and 76% respectively. Three patients showed negative CDUS and CEUS and positive FNB results; follow-up confirmed malignant thrombosis in these patients. One patient showed negative CDUS, CEUS, and FNB findings. Howewer, follow-up of the thrombus showed US signs of malignancy. Another FNB confirmed HCC infiltration of the portal vein. Conclusion CEUS seems to be the most sensitive and specific test for diagnosing malignant portal vein thrombosis in patients with cirrhosis.