Efficacy of ¹⁸F-FDG PET/CT in the differential diagnosis of benign and malignant solitary pulmonary nodules

Objective: To analyze the value of maximum standardized uptake value (SUV_max) of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in differentiating the malignant solitary pulmonary nodules (SPN) from benign ones. Methods: ¹⁸F-FDG PET/CT imaging data of 84 patients (39 males, 45 females; age: 34-81 (average: 61.1) years) with SPN in the First People's Hospital of Lianyungang between September 2017 and June 2019 were retrospectively analyzed. The pathological results were taken as the gold standard. Differences of SUV_max between benign and malignant SPN were analyzed with Mann-Whitney U test, and the best cut-off value for the diagnosis of benign and malignant SPN was measured by receiver operating characteristic (ROC) curve. The diagnostic efficacy was analyzed based on SUV_max. Results: The pathological results confirmed 54 patients with malignant SPN, and 30 patients with benign SPN. SUV_max of malignant group was significantly higher than that of benign group (5.48 ± 4.08 vs 1.70 (0.73, 3.33); U = 443.50, P = 0.001). The 84 SPN included 58 solid SPN and 26 subsolid SPN. SUV_max of malignant subsolid SPN and benign ones were not significantly different (U = 56.00, P > 0.05). The diagnostic value of SUV_max in 58 cases of solid nodules were analyzed based on ROC curves, and the optimal cut-off value was 1.85. The corresponding diagnostic sensitivity, specificity, accuracy, negative predictive value and positive predictive value were 97.06% (33/34), 62.50% (15/24), 82.76% (48/58), 15/16, 78.57% (33/42), respectively. Conclusions: ¹⁸F-FDG uptake of malignant SPN were higher than benign ones. The diagnosis of benign and malignant solid SPNs based on SUV_max 1.85 has high sensitivity, negative predictive value and accuracy. SUV_max has limited diagnostic value on subsolid SPN. (authors)