The Value of [ ¹⁸ F]FDG PET/CT for Differentiating Neoplastic From Benign Thrombus

ABSTRACT Background Vascular thrombus is a common complication in cancer patients and can be classified as benign or neoplastic based on tumor cell presence. Conventional imaging modalities provide anatomical information but exhibit limited specificity in distinguishing neoplastic from benign thrombi, prompting the evaluation of 2‐deoxy‐2‐[ 18 F]fluoro‐D‐glucose positron emission tomography/computed tomography ([ 18 F]FDG PET/CT), which leverages metabolic differences for improved differentiation. In this study, the efficacy of [ 18 F]FDG PET/CT for differentiating neoplastic thrombus from benign thrombus was evaluated in patients with malignant tumors. Methods Sixty‐five patients with histologically or clinically confirmed neoplastic or benign thrombus who underwent [ 18 F]FDG PET/CT were retrospectively enrolled. Both visual and semi‐quantitative analyses of the PET/CT scans were conducted. The difference in maximum standardized uptake value (SUV max ) between neoplastic and benign thrombus was assessed using a t ‐test. Furthermore, receiver operating characteristics (ROC) analysis was performed to determine the optimal SUV max threshold for differentiating neoplastic from benign thrombus. Results Within the cohort, 55 patients were diagnosed with neoplastic thrombus and 10 patients with benign thrombus. In the visual analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of [ 18 F]FDG PET/CT for diagnosing neoplastic thrombus were 96.4%, 90.0%, 98.1%, 81.8%, and 95.4%, respectively. In the semi‐quantitative analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for diagnosing neoplastic thrombus were 96.4%, 100%, 100%, 83.3%, and 96.9%, respectively. The normalized SUV max of neoplastic thrombus was significantly higher than that of benign thrombus (10.11 ± 5.32 vs. 2.21 ± 0.51, p < 0.001). The area under the ROC curves for visual assessment and semi‐quantitative analysis were 0.932 and 0.993, respectively. There was no statistically significant difference observed between these two assessment methods ( p = 0.317). Conclusions [ 18 F]FDG PET/CT is capable of differentiating neoplastic thrombus from benign thrombus. Both visual and semi‐quantitative analyses demonstrated high diagnostic sensitivity, specificity, and accuracy.