¹⁸F-FDG and ¹⁸F-NaF PET/CT demonstrate coupling of inflammation and accelerated bone turnover in rheumatoid arthritis

Abstract

Objective. To compare the findings in rheumatoid arthritis (RA)-affected joints between ¹⁸F-fluorodeoxyglucose (FDG) and ¹⁸F-fluoride (NaF) positron emission tomography (PET)/computed tomography (CT).

Methods. We enrolled twelve RA patients who started a new biologic agent (naïve 9 and switch 3). At entry, both hands were examined by ¹⁸F-FDG PET/CT, ¹⁸F-NaF PET/CT, and X-ray. Intensity of PET signals was determined by standardized uptake value max (SUVmax) in metacarpophalangeal (MCP), proximal interphalangeal (PIP), and ulnar, medial, and radial regions of the wrists. Hand X-rays were evaluated according to the Genant-modified Sharp score at baseline and 6 months.

Results. Both ¹⁸F-FDG and ¹⁸F-NaF accumulated in RA-affected joints. The SUVmax of ¹⁸F-FDG correlated with that of ¹⁸F-NaF in individual joints (r = 0.65), though detail distribution was different between two tracers. ¹⁸F-NaF and ¹⁸F-FDG signals were mainly located in the bone and the surrounding soft tissues, respectively. The sum of SUVmax of ¹⁸F-NaF correlated with disease activity score in 28 joint (DAS28), modified health assessment questionnaire (MHAQ), and radiographic progression. ¹⁸F-FDG and ¹⁸F-NaF signals were associated with the presence of erosions, particularly progressive ones.

Conclusion. Our data show that both ¹⁸F-FDG and ¹⁸F-NaF PET signals were associated with RA-affected joints, especially those with ongoing erosive changes.

Keywords:

• ¹⁸F-FDG PET
• ¹⁸F-NaF PET
• Bone turnover
• Rheumatoid arthritis

Acknowledgements

This work was supported in part by grants from 2013 grant of Yokohama Foundation for Advancement of Medical Science (to Takase-Minegishi). We thank all the colleagues in our laboratories for their kind cooperation in this project. We also thank Mr. Tom Kiper for his review of the manuscript.

Conflict of interest

None.

Supplementary material available online

Supplementary Tables 1, 2 and Figure 1 to be found online at http://informahealthcare.com/doi/abs/10.3109/14397595.2015.1069458