Objective To explore a quantitative scoring system based on PET/CT and high-resolution computed tomography(HRCT) characteristics for differentiating benign and malignant solitary pulmonary lesions.

Methods A total of 112 patients with solitary pulmonary lesions detected by ¹⁸F-FDG PET/CT were enrolled and reviewed retrospectively. Of these cases, 44 were benign lesions and 68 were malignant. PET/CT and HRCT imaging features were recorded and evaluated. A quantitative scoring system was established. The best cut-off score was calculated by analysis of receiver operating characteristics(ROC) in differentiating benign and malignant lesions.

Results The indicators of malignant solitary pulmonary lesions by PET/CT and HRCT included age≥60 years(2 points), diameter of the lesion≥1 cm(2 points), heterogeneous density(2 points), clear boundary(1 point), SUV_max≥2.5(2 points), ΔSUV_max≥1.0(2 points), retention index(RI)≥15%(2 points), lobular sign(3 points), spiculation sign(3 points), pleural traction sign(3 points), and vacuole sign(3 points). A quantitative scoring system was established according to risk factors. Moreover, score 12 was the best cut-off by ROC analysis in differentiating benign and malignant lesions. The sensitivity and specificity rates were 92.6% and 81.8%, respectively. Conclusion The quantitative scoring system based on PET/CT and HRCT features exhibited a good capacity for differentiating malignant lesions from benign solitary pulmonary lesions.