Can multimodality imaging using 18F-FDG/18F-FLT PET/CT benefit the diagnosis and management of patients with pulmonary lesions?

Dual-tracer, 18F-fluorodeoxyglucose and 18F-fluorodeoxythymidine (18F-FDG/18F-FLT), dual-modality (positron emission tomography and computed tomography, PET/CT) imaging was used in a clinical trial on differentiation of pulmonary nodules. The aims of this trial were to investigate if multimodality imaging is of advantage and to what extent it could benefit the patients in real clinical settings. Seventy-three subjects in whom it was difficult to establish the diagnosis and determine management of their pulmonary lesions were prospectively enrolled in this clinical trial. All subjects underwent 18F-FDG and 18F-FLT PET/CT imaging sequentially. The images were interpreted with different strategies as either individual or combined modalities. The pathological or clinical evidence during a follow-up period of more than 22 months served as the standard of truth. The diagnostic performance of each interpretation and their impact on clinical decision making was investigated. 18F-FLT/18F-FDG PET/CT was proven to be of clinical value in improving the diagnostic confidence in 28 lung tumours, 18 tuberculoses and 27 other benign lesions. The ratio between maximum standardized uptake values of 18F-FLT and 18F-FDG was found to be of great potential in separating the three subgroups of patients. The advantage could only be obtained with the full use of the multimodality interpretation. Multimodality imaging induced substantial change in clinical management in 31.5% of the study subjects and partial change in another 12.3%. Multimodality imaging using 18F-FDG/18F-FLT PET/CT provided the best diagnostic efficacy and the opportunity for better management in this group of clinically challenging patients with pulmonary lesions. (orig.)