NaF-PET shows bone formation in patients with psoriatic arthritis

“F-18 NaF PET/CT may be a new clinically valuable tool to detect whole-body disease activity of PsA, reflected by new bone formation in all PsA disease domains represented in a single scan,” said a team led by the PhD candidate. Jerney de wrote Jongh. The study was published Nov. 12 in the European Journal of Nuclear Medicine and Molecular Imaging.

PsA is a chronic and inflammatory musculoskeletal disorder associated with psoriasis and various musculoskeletal manifestations, especially enthesitis, a painful inflammation where tendons or ligaments attach to bone. Enthesitis activity in PsA may be associated with new bone formation.

Clinical assessment of enthesitis is challenging and has limited accuracy, as it relies only on the presence of tenderness and general soft tissue swelling, the authors said. In addition, other imaging approaches, such as ultrasound and MRI, have proven limited in identifying these sites, they wrote.

In this study, the researchers enrolled 16 patients with a clinical diagnosis of psoriatic arthritis from a rheumatology center at Amsterdam UMC. Patients underwent whole-body PET/CT scans 45 minutes after injection with F-18 NaF, a radiotracer that can identify new bone formation based on osteoblastic activity.

F-18 NaF improvement in the right wrist and proximal interphalangeal joints of the hands

F-18 NaF supplementation in the right wrist and proximal interphalangeal joints of the hands (A), at the patellar tendon insertion (B), in the metatarsophalangeal and interphalangeal joints of the feet and right Achilles tendon (C), and in the distal interphalangeal joints of the hands (D). Image courtesy of the European Journal of Nuclear Medicine and Molecular Imaging.

According to the study results, 81.8% of PET-positive joints were missed on clinical assessment. The team found that only 18.2% of PET-positive joints were clinically positive (that is, tender or swollen). But most of the PET negative sites were also clinically negative (611/638). Similar results were found for entheses, with 70.5% of PET-positive entheses missed on clinical evaluation and 29.5% of PET-positive entheses identified clinically.

De Jongh and colleagues acknowledged that their study cohort was small and urged further research.

“The clinical relevance of asymptomatic PET lesions in PsA needs to be further explored in longitudinal studies, relating PET outcome to clinical and radiological follow-up over time,” the researchers concluded.

Copyright © 2022

Leave a Comment