18F-Fluorodeoxyglucose Positron Emission Tomography Imaging Assessment Within a Randomized Controlled Trial in Giant Cell Arteritis.
Kaitlin A Quinn, Sovira Tan, Pauline Verdijk et al.
✦ AI-curated · Sources linked
In 30 seconds
This imaging analysis within an international, multicenter randomized controlled trial compared FDG-PET with clinical and laboratory assessments in patients with new-onset or relapsing giant cell arteritis receiving guselkumab or placebo plus tapered glucocorticoids. At baseline, scans showed active vasculitis in 28 (55%) of 51 patients, without association with symptoms, acute phase reactants, or flare risk. PET activity was present in 17 of 21 (81%) patients at clinical flare and 14 of 20 (70%) at week 52. Persistent PET activity or inactivity in some patients was independent of clinical assessment, indicating potential discordance between imaging and clinical disease measures.
Key findings
- Baseline PET showed active vasculitis in 28 (55%) of 51 patients and was not associated with symptoms, acute phase reactants, or flare risk.
- PET scans were active in 17 of 21 (81%) patients during clinical flare and 14 of 20 (70%) at week 52.
- Some patients had persistently active (n = 21) or inactive (n = 9) scans across visits, independent of clinical assessment.
Why it matters
The findings show that vascular FDG uptake and clinical disease assessments may not align in giant cell arteritis. This matters when interpreting imaging as a marker of disease activity or as an outcome in therapeutic studies: PET activity alone may not reflect symptoms, laboratory findings, or flare risk. The study supports caution in treating imaging results as interchangeable with clinical assessment.
What to keep in mind
PET was assessed at baseline and at flare or week 52, and the reported findings come from subsets with available scans; the abstract does not establish how PET discordance relates to longer-term outcomes.