PET/CT (Positron Emission Tomography / Computed Tomography) showed a discriminating value in measuring disease activity in large-vessel vasculitis (LVV). This finding was consistent in giant cell arteritis (GCA) and Takayasu’s arteritis (TAK) subgroups. Therefore, PET/CT could be a reliable tool in the assessment of disease activity in LVV. Surprisingly, higher PET Vascular Activity Score (PETVAS) scores during clinical remission were not predictive of future relapses.
Disease activity assessment in LVV lacks validated scoring systems. PET/CT might be the imaging biomarker that is needed. The current study assessed whether PETVAS can discriminate between clinically active and inactive LVV (both GCA and TAK) in a single-centre cohort study.
LVV patients (n=100) were followed from 2007 until 2020 and received complete assessments (clinical, laboratory, imaging) at baseline, annually, and when relapse was suspected. PETVAS was calculated for each PET/CT scan and compared to the clinical examination of disease activity status. Dr Elena Galli (University of Modena and Reggio Emilia, Italy) presented the results.
Logistic regression analysis demonstrated that higher PETVAS scores were associated with clinically active LVV (OR 1.15; P<0.0001). This result was consistent in the GCA (OR 1.12; P<0.0001) and TAK (OR 1.22; P<0.0001) subgroups. The computed ROC curves demonstrated acceptable predictive values in the total population (AUC 0.73) and in the GCA (AUC 0.70) and TAK (AUC 0.79) subgroups. Nevertheless, higher PETVAS scores during low clinical disease activity were not associated with a higher risk of relapse. According to Galli, this finding is not well understood and needs to be unravelled in future research.
Galli E, et al. The role of positron emission tomography/computed tomography (PET/CT) in disease activity assessment in patients with large vessel vasculitis. OP0069, EULAR 2021 Virtual Congress, 2-5 June.