Serial assessment of ultrasound sensitivity and scores in patients with giant cell arteritis before and 3 and 10 days after treatment

Abstract

Objectives: The objective of this study was to evaluate the sensitivity and scores of vascular US before and after initiating glucocorticoid (GC) treatment in patients with new-onset giant cell arteritis (GCA).

Methods: Treatment-naïve patients with GCA were prospectively included. 18F-fluorodeoxyglucose (18F-FDG) PET/CT, US and temporal artery (TA) biopsy were performed in all patients. US was repeated 3 and 10 days after GC commencement. Intima-media thickness and presence of halo signs were assessed. Sonographers were unblinded to the clinical data. The OMERACT GCA Ultrasonography score (OGUS) and the halo count (HC) were calculated.

Results: Forty-eight patients were included. Before GC exposure, US sensitivity was 94% (95% CI: 83-99), 73% (95% CI: 58-85), and 71% (95% CI: 56-83) when assessing all vessels, TAs, and large vessels (LVs), respectively. At day 3 and 10, the overall US sensitivity was 92% (95% CI: 78-98, P = 0.16) and 83% (95% CI: 69-92, P = 0.10), respectively. At day 10, the TA-US and LV-US sensitivity was 53% (95% CI: 38-68, P < 0.01) and 60% (95% CI: 44-74, P = 0.13), respectively. The median OGUS decreased from 1.06 (IQR 0.83-1.24) to 0.95 (IQR 0.78-1.14, P < 0.01) and 0.90 (IQR 0.73-1.01, P < 0.001) after 3 and 10 days, respectively. The median HC decreased from 3 (IQR 2-5) to 2 (IQR 1-4, P < 0.01) after 10 days.

Conclusion: The vasculitic US findings expressed by OGUS diminished after 3 days of GC treatment. TA-US sensitivity decreased after 10 days, whereas LV-US was less likely to change, highlighting the importance of LV-assessment. Consistent with the EULAR recommendations, these findings encourage prompt US assessment, preferably within 3 days, to ensure an accurate diagnosis.

Keywords: diagnosis; giant cell arteritis; large-vessel vasculitis; sensitivity; vascular ultrasound.