Application of [ 18 F]NaF and [ 18 F]FDG PET/CT to Assess Molecular Calcification and Glucose Metabolism in Thyroid Cartilage

Objective Thyroid cartilage calcification and glucose metabolism may vary with age and gender. This study investigated the role of [ 18 F]-sodium fluoride ([ 18 F]NaF) and 2-[ 18 F]fluoro-2-deoxy-D-glucose ([ 18 F]FDG) PET/CT in evaluating of physiological molecular calcification and glucose metabolism of thyroid cartilage with age. Methods This retrospective study analyzed [ 18 F]NaF and [ 18 F]FDG PET/CT images from the CAMONA study (NCT01724749). Regions of interest were placed around the thyroid cartilage on CT images using OsiriX software. The mean standardized uptake value (SUVmean) was measured for [ 18 F]NaF and [ 18 F]FDG PET/CT images. Pearson correlation coefficients were calculated to evaluate the effects of aging on [ 18 F]NaF and [ 18 F]FDG in the thyroid cartilage. Results A total of 127 healthy subjects (65 females and 62 males) with a mean age of 48.46 ± 14.13 (range 21–75) years for [ 18 F]NaF PET/CT and 114 healthy subjects (52 females and 62 males) with a mean age of 49.05 ± 14.29 (range 22–75) years for [ 18 F]FDG PET/CT were included. A significant positive correlation was observed between age and SUVmean of [ 18 F]NaF in the thyroid cartilage (r = 0.18, p = 0.04), indicating that molecular calcification of this cartilage increases with aging. However, the correlation between age and SUVmean of [ 18 F]FDG in the thyroid cartilage was not statistically significant (r = -0.09, p = 0.31). Conclusion This study presents a novel methodology for the determination of molecular calcification and glucose metabolism of laryngeal cartilage using [ 18 F]NaF and [ 18 F]FDG PET/CT. Molecular calcification of thyroid cartilage increase with age, whereas glucose metabolism did not show a statistically significant correlation with age.