Quantitative evaluation of normal spinal osseous metabolism with 18F-NaF PET/CT

OBJECTIVE: The aim of this study was to describe osseous metabolic activity with respect to age and weight in the spine as expressed through fluorine-18-sodium fluoride (F-NaF) uptake in a healthy male population. PARTICIPANTS AND METHODS: Whole-body F-NaF PET/CT scans of healthy male participants (22-71 years, 50-145 kg, n=47) were analysed using a global assessment methodology to derive the mean standardized uptake values (SUVmean). Individual regions of the spine (cervical, thoracic and lumbar) along with the aggregate whole spine were assessed and compared as potential functions of age and body weight. RESULTS: Older participants did not have higher F-NaF uptake than younger participants (whole spine, P=0.93; cervical, P=0.12, thoracic, P=0.93; lumbar, P=0.42), whereas increasing body weight was associated with greater tracer uptake (whole spine P=0.003; cervical P=0.01; thoracic P=0.002; lumbar P=0.004). Both the thoracic (average SUVmean=4.864±1.338) and lumbar (average SUVmean=4.939±1.284) spines had significantly elevated (P≤0.0001) uptake compared with the cervical spine (average SUVmean=3.969±1.024). CONCLUSION: We assessed the metabolic activity of the spine's osseous tissues with F-NaF PET using a global assessment approach in healthy men. Our study provides evidence of differences in spinal metabolism as related to weight, but not age. Our study offers a foundation for future larger studies in symptomatic populations.