The effects of limb laterality and age on the inflammation and bone turnover of the acromioclavicular shoulder joint: 18 F-fluorodeoxyglucose and 18 F-sodium-fluoride-PET/computed tomography study.

Purpose: The acromioclavicular (AC) joint is a common site of injury and degenerative changes such as osteoarthritis (OA) of the shoulder. Physical manifestations of OA are preceded by molecular changes, detection of which may enhance early prophylaxis and monitoring of disease progression. In this study, we investigate the use of 18 F-FDG and 18 F-NaF-PET/CT to assess the effects of limb laterality and age on the inflammation and bone turnover of the AC shoulder joint.

Methods: We analyzed FDG and NaF-PET/CT scans of 41 females (mean age of 43.9 ± 14.2 years) and 45 males (mean age of 44.5 ± 13.8 years) using a semiquantitative technique based on predefined ROI.

Results: There was a greater NaF uptake in the right side of the AC joint compared with the left in both females (left: 2.22 ± 1.00; right: 3.08 ± 1.18; P < 0.0001) and males (left: 2.57 ± 1.49; right: 2.99 ± 1.40; P = 0.003). No consistent correlation between age and NaF or FDG uptakes were found in both females and males. There was also a positive correlation between FDG and NaF uptakes in both left ( P = 0.01; r = 0.37) and right ( P = 0.0006; r = 0.53) AC joints of male subjects.

Conclusion: Our study is the first to reveal the varying effect of right-left limb laterality and aging on FDG and NaF uptake at the AC joint. Future studies correlating the history of shoulder trauma, pain, and degenerative change with FDG and NaF-PET/CT findings will be critical in the adoption of molecular imaging in the clinical setting.