¹⁸F-sodium fluoride PET/CT as a complementary measure of osteoblastic disease burden in axial spondyloarthritis: a prospective exploratory study.
Hung-Yi Chen, Yu-Li Chiu, Sin-Yi Lyu et al.
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In 30 seconds
This prospective exploratory imaging study assessed whether sacroiliac joint (SIJ) ¹⁸F-sodium fluoride PET/CT could complement MRI in 43 adults with chronic low back pain classified as radiographic axial spondyloarthritis/ankylosing spondylitis (AS), non-radiographic axial spondyloarthritis, or degenerative joint disease. SIJ SUVmax correlated with MRI inflammation and structural scores (ρ = 0.629 and ρ = 0.606, respectively; both p < 0.001). Median SUVmax was higher in AS than in the other groups, and uptake was present in many AS patients without MRI-defined bone marrow edema.
Key findings
- SIJ SUVmax correlated with MRI inflammation (ρ = 0.629) and structural scores (ρ = 0.606); both p < 0.001.
- Median SIJ SUVmax was 14.7 [11.2-22.4] in AS, 5.5 [4.4-9.9] in nr-axSpA, and 5.7 [4.0-9.2] in DJD (p = 0.001).
- Visually positive SIJ uptake occurred in 23/29 (79.3%) patients with AS, including 10/16 without MRI-defined bone marrow edema.
Why it matters
The findings suggest that ¹⁸F-NaF PET/CT may capture osteoblastic activity associated with both inflammatory and structural MRI features, including in some patients without MRI-defined edema. This could provide complementary information when characterising axial spondyloarthritis disease burden, although the study does not establish diagnostic thresholds or show that PET/CT improves clinical outcomes.
What to keep in mind
This was a small, exploratory study, and the authors state that derived thresholds require external validation.