The role of 18F-FDG PET/CT in distinguishing benign from malignant portal vein thrombosis

Background Diagnosis of tumour thrombosis and differentiating it from benign thrombosis are essential for managing patients, planning treatments, and minimising unneeded anticoagulation therapy. Bland thrombi occur in both cancer and non-cancer patients; tumour thrombi and bland can coexist. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F - FDG PET/CT) is useful in detecting and diagnosing tumour thrombosis and distinguishing it from benign thrombosis. Objective This study’s aim was to assess the value of 18F - FDG PET/CT in distinguishing benign from malignant portal vein thrombosis (PVT) in liver cirrhosis patients. Methods A retrospective study was conducted on 38 patients who had PVT that was histopathologically confirmed and performed 18F- FDG PET/CT scans at our institute between January 2021 and April 2022. For all patients, sociodemographic data, visual analysis, semiqualitative analysis (SUV max value), and associated hepatic pathology were collected. Results The SUV max values were significantly higher in the tumour thrombosis group (6.26 ± 1.94), compared to the bland thrombosis group (1.79 ± 0.69), ( P < 0.001). The ROC curve of semiqualitative analysis (SUV max ) revealed a sensitivity of 96.3% and a specificity of 36.4%, at area under curve of 0.827 with SUV max > 3.5 as the pathological cut-off value to distinguish tumour from bland thrombi. Conclusions By using semiqualitative analysis, 18F - FDG PET/CT is a valuable new technique in differentiating between neoplastic and bland PV thrombi, with optimal cut-off SUVmax value > 3.5 as a criterion.