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

Aims: In this retrospective study, we evaluated the role of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in differentiating malignant from benign portal vein thrombosis (PVT) in patients with known malignant tumors.
Methods: Seventy-two patients with histologically or clinically confirmed PVT and who had undergone (18)F-FDG PET/CT were included. Visual and semiquantitative analyses of PET/CT scans were performed. Metabolic activity was measured using the maximum standardized uptake value (SUVmax) by drawing the region of interest at the site of thrombosis. Receiver operating characteristic analysis was conducted to identify the optimal cutoff of SUVmax for detecting neoplastic thrombosis. Malignancy was defined using the following criteria: (1) visual analysis and (2) SUVmax >3.35. PET/CT results were confirmed with histopathological results and clinical and imaging follow-up.
Results: The SUVmax of tumor thrombus (6.37 ± 2.67) was significantly higher than that of bland thrombus (2.87 ± 1.47; P < 0.01). The sensitivities, specificities, and accuracies for the two criteria were 91.5 % and 93.6; 64.0 and 80.0 %; and 81.9 % and 88.9 %, respectively.
Conclusion: (18)F-FDG PET/CT is a promising new method for distinguishing between portal venous neoplastic thrombosis and bland thrombosis using semiquantitative analysis, with the optimal cutoff value of SUVmax >3.35 as a criterion.