18F-sodium fluoride PET-CT visualizes bone formation in psoriatic arthritis patients: Study

For this purpose, the researchers included sixteen patients with PsA fulfilling Classification criteria for Psoriatic arthritis (CASPAR) criteria or clinical PsA diagnosis according to a rheumatologist and with ≥ 1 clinically active enthesitis site.

A whole-body 18F-NaF PET-CT scan was performed on each patient. The researchers scored all scans for PET-positive lesions at enthesis sites, peripheral joints, and the spine. Assessment of clinical disease activity was done by swollen/tender joint count 44, enthesitis as per the MASES (Maastricht Ankylosing Spondylitis Enthesitis Score; range 0-13) and SPARCC (Spondyloarthritis Research Consortium of Canada (SPARCC; range 0-16).

The study demonstrated the following findings:

• One hundred nine joints showed PET enhancement out of 1088 evaluated joints, primarily in the metatarsal and interphalangeal joints of the feet (12.9%) and the distal interphalangeal joints of the hands (12.9%).
• The authors found PET positivity at 44/464 enthesis sites, mainly at the quadriceps tendon insertion (10/44, 22.7%) and patella tendon insertion (11/44, 25%)
• 18.2% and 29.5% were clinically positive of the PET-positive joints and enthesis sites; 81.8% and 70.5% of the PET-positive joints and entheses were clinically asymptomatic.
• The researchers observed ≥ 1 axial PET-positive lesion in 11 patients, mainly in the cervical spine.

"18F-NaF PET-CT scans can visualize the formation of new bone, indicating local PsA activity, at all peripheral disease activity sites and perhaps in the axial skeleton," the authors wrote.

"18F-NaF PET-CT may add information to the assessment of clinical disease activity, indicated by a high number of clinically negative, PET-positive sites in addition to concordant findings," they concluded.

Reference:

de Jongh, J., Hemke, R., Zwezerijnen, G.J.C. et al. 18F-sodium fluoride PET-CT visualizes both axial and peripheral new bone formation in psoriatic arthritis patients. Eur J Nucl Med Mol Imaging (2022). https://doi.org/10.1007/s00259-022-06035-w