Total Lesion Glycolysis Obtained by FDG PET/CT in Diagnosing Solitary Pulmonary Nodules

Objective: To evaluate the diagnostic performance of total lesion glycolysis (TLG) obtained by 18F-FDG PET/ CT to differentiate malignant solitary pulmonary nodules (SPNs) from benign ones. Study Design: Observational study. Place and Duration of Study: Department of Nuclear Medicine, Istanbul Medeniyet University School of Medicine, Istanbul, Turkey, from January 2018 to April 2022. Methodology: Eighty patients, who were found to have SPNs and underwent PET/CT imaging, were enrolled in this retrospective study. Parameters of PET-CT such as metabolic, volumetric, and metabolovolumetric were assessed concerning diagnostic value. Moreover, maximum standard uptake value (SUVmax) and TLG were combined and compared to improve diagnostic accuracy. Results: The number of the detected benign and malignant SPNs was 38 and 42, respectively. Compared to the benign lesions, the malignant nodules presented significantly higher values in terms of SUVmax, TLG, and the volumes of metabolic tumour (MTV) and CT. Considering all parameters, the highest area under the curve (AUC) was occupied by TLG and SUVmax. The values for the sensitivity, specificity, and accuracy of SUVmax, TLG, and SUVmax combined with TLG were as follows respectively: 97.6%, 63.2%, and 81.2%; 85.7%, 92.1%, and 88.7%; and 85.7%, 94.7%, and 90%. Conclusion: The conventional value of SUVmax does not yield satisfactory results in order to separate the malignant nodules from the benign ones. The SUVmax value could be more valuable if it is used with TLG measurement in diagnosing SPNs. Key Words: 18F-FDG PET/CT, SUVmax, TLG, Pulmonary nodule.