Evaluation of Cavitary Lung Lesions with 18F-FDG PET/CT: Differentiating Benign from Malignant Lesions.
Objectives This study aimed to analyze 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features to differentiate benign from malignant pulmonary cavitary lesions. Methods A total of 76 patients with cavitary lung lesions who underwent 18F-FDG PET/CT imaging were retrospectively analyzed. Patient demographics, histopathological findings, cavitary lesion morphology, CT characteristics, and maximum standard uptake value (SUVmax) of lesions were recorded. Cavitary lesions were classified as benign or malignant and further subdivided by maximum wall thickness into two groups: ≤15 mm and >15 mm. Histopathological results, clinical follow-up, or both were used as the reference standard for lesion classification. Results Among 76 patients (mean age, 63.4 years), 31 (40.8%) had benign disease and 45 (59.2%) had malignant disease. Malignant lesions were observed at older ages and exhibited significantly greater lesion size, wall thickness, and SUVmax than those in benign lesions (p<0.05 for all). There were no significant differences between the malignant and benign groups regarding sex, lesion localization, air-fluid levels, or pleural effusion (p>0.05 for all). Peripheral consolidation, multiple cavitary lesions, and tree-in-bud pattern were significantly more prevalent in benign lesions than in malignant lesions (p<0.05 for all). In lesions with a maximum wall thickness ≤15 mm, SUVmax was significantly higher in malignant lesions than in benign lesions (mean values, 9.81 vs. 5.28; p<0.05). Malignant lesions with a maximum wall thickness >15 mm demonstrated higher SUVmax values (mean 18.37 vs. 10.45; p<0.05). SUVmax was independently associated with malignancy (odds ratio: 1.237, p=0.017) and showed the best diagnostic performance (area under the curve=0.866; cut-off 8.58, sensitivity 80%, specificity 77%). Conclusion The morphological characteristics of pulmonary cavitary lesions, associated parenchymal findings, and 18F-FDG uptake patterns on PET/CT provide valuable information for distinguishing between benign and malignant lesions. In this study, SUVmax demonstrated the highest diagnostic performance. The combined evaluation of metabolic and morphological parameters can enhance diagnostic accuracy and support the clinical decision-making process, thereby contributing to the optimal management of patients.