Assessment of Takayasu arteritis in routine practice with PETVAS, an 18F-FDG PET quantitative scoring tool.

Background: The aim of this study was to evaluate the value of the PET vascular activity score (PETVAS) during the follow-up of patients with Takayasu arteritis.

Methods: Takayasu arteritis patients who underwent 18F-Fluorodeoxyglucose (FDG) PET imaging were evaluated retrospectively. In 8 patients both 1 and 2-h imagings were also performed prospectively. For PETVAS, 9 arterial areas were scored between 0-3 according to the FDG uptake.

Results: Forty-six images of 34 patients were evaluated. PETVAS was higher in patients with clinically active disease (p = 0.03) and in the C-reactive protein (CRP) elevated group among clinically inactive patients (p = 0.0015). PETVAS correlated with CRP (p = 0.003, r = 0.53) and erythrocyte sedimentation rate (p = 0.005, r = 0.41), whereas age, disease duration, immunosuppressive, and glucocorticoid (GC) treatments were not associated with PETVAS. First vs. 2nd-h PETVAS was similar in patients who had both 1st and 2nd h PET scans (p = 0.67).

Discussion: We observed higher PETVAS in patients with active disease and elevated acute phase reactants. Although scores in our study (performed at one-h) were lower compared to the original PETVAS study performed at two h, PETVAS seems to be a reliable tool to quantify FDG PET scores in routine practice.