High metabolism thrombus of the portal vein: 18F fluorodeoxyglucose positron emission tomography/computer tomography demonstration and clinical significance in hepatocellular carcinoma

Abstract

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Objectives: To select an appropriate treatment regimen, it is essential to accurately characterize the nature of a thrombus in hepatocellular carcinoma (HCC) patients. This study assessed the ability of FDG PET/CT to differentiate between benign and malignant portal vein thrombosis in HCC patients.

Methods: Five consecutive patients who had HBV cirrhosis, biopsy-proved HCC, and thrombosis of the main portal vein and/or left/right portal vein on US, CT or MRI were studied with FDG PET/CT. Presence or absence of high metabolism thrombus on FDG PET/CT were considered diagnostic for malignant or benign portal vein thrombosis. All patients were followed-up monthly by US, CT or MRI. Shrinkage of the thrombus and/or recanalization of the vessels on US, CT or MRI during follow-up was 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.

Results: Follow-up (1 to 10 months) showed signs of malignant thrombosis in 4 of 5 patients. US, CT or MRI produced a true-positive result for malignancy in 4 of 5 patients, a false-positive result in 1of 5 patients. FDG PET/CT showed high metabolism thrombus in 4 of 5 patients. FDG PET/CT was true positive in 4 of 5 patients, a true-negative result in 1 of 5 patients. No false-positive result was observed at FDG PET/CT.

Conclusions: FDG PET/CT can be helpful in discriminating between benign and malignant portal vein thrombi. Those patients may benefit from FDG PET/CT, when portal vein thrombi can not be diagnosed exactly by US, CT or MRI.