The clinical efficacy of 18F-FDG-PET/CT in benign and malignant musculoskeletal tumors

Objective Most of the current clinical data on the role of 2-[F-18]fluoro-2-deoxy-D-glucose positron emission tomography (F-18-FDG-PET) in musculoskeletal tumors come from patients studied with PET and less frequently with hardware fusion PET/computed tomography (CT). And the number of cases in each report is too small to clarify the exact clinical efficacy of PET or PET/CT. This prompted us to analyze our experience with F-18-FDG-PET/CT in a relatively large group of patients with musculoskeletal tumors. Methods F-18-FDG-PET/CT was performed on 91 patients from May 2004 to June 2007. The final diagnosis was obtained from surgical biopsy in 83 patients (91%) and clinical follow-up in 8 (9%). We analyzed the characteristics and amount of F-18-FDG uptake in soft tissue and bone tumors, and investigated the ability of F-18-FDG-PET/CT to differentiate malignant from benign tumors. The cutoff maximum standardized uptake value (SUVmax) was calculated using the receiver-operation characteristic curve method. Sensitivity, specificity, and diagnostic accuracy were calculated with cutoff SUVmax and the final diagnosis. Unpaired t test was used for the statistical analysis. Results Final diagnosis revealed 19 benign soft tissue tumors (mean SUVmax 4.7), 27 benign bone tumors (5.1), 25 malignant soft tissue tumors (8.8), and 20 malignant bone tumors (10.8). There was a significant difference in SUVmax between benign and malignant musculoskeletal tumors in total (P < 0.002), soft tissue tumors (P < 0.05), and bone tumors (P < 0.02). Sensitivity, specificity, and diagnostic accuracy were 80%, 65.2%, and 73% in total with cutoff SUVmax 3.8, 80%, 68.4%, and 75% in the soft tissue tumors with cutoff SUVmax 3.8, and 80%, 63%, and 70% in the bone tumors with cutoff SUVmax 3.7. Conclusions F-18-FDG-PET/CT reliably differentiated malignant soft tissue and bone tumors from benign ones, although there were many false-positive and false-negative lesions. Further studies with all kinds of musculoskeletal tumors in large numbers are needed to improve the diagnostic accuracy of F-18-FDG-PET/CT.