Inclusion criteria for the qualitative analysis were (1) <sup>18</sup>F-FDG PET used to assess the disease activity, (2) The use of the ACR criteria for the diagnosis of TAK, (3) No case mixed vasculitis (i.e., no giant cell arteritis), and (4) CRP concentration and clinical disease activity available.
The utility of the ACR/EULAR 2017 provisional classification criteria for granulomatosis with polyangiitis in Korean patients with antineutrophil cytoplasmic antibody-associated vasculitis.
Since publication of the ACR criteria for vasculitis, the sensitivity for each type of vasculitis, except GCA, has diminished, although the specificities have remained high, highlighting the need for updated classification criteria.