Change in arterial damage from baseline to follow-up is depicted in 1,091 arterial territories from 70 patients with large-vessel vasculitis (577 arterial territories from patients with TAK and 514 arterial territories from patients with GCA). The presence of FDG-PET activity and existing arterial damage in each arterial territory was assessed at time of baseline imaging studies. Over a median 1.6-year follow-up period, the number of arterial territories with improved damage, worsened damage, new damage, or no change was evaluated. TAK=Takayasu’s arteritis; GCA=giant cell arteritis