The Great Debate: Ultrasound vs. Temporal Artery Biopsy in Giant Cell Arteritis Michael Cammarata, MD, RhMSUS | December 10, 2025In the ACR Convergence 2025 session, Great Debate: Ultrasound vs. Temporal Artery Biopsy in Giant Cell Arteritis, two vasculitis experts went head to head to determine the ideal first test in the diagnosis GCA: ultrasound or biopsy.