The inter-observer agreement was excellent in this study (kappa ≥ 0.85) and even higher than a previous validation (kappa = 0.76).8 Considering the importance of early diagnosis and treatment in neuroinflammatory diseases, this study is meaningful to confirm an additional value of brain lesion distribution criteria at disease onset, which enabled the distinction of MS from NMOSD and MOG-EM. Here, MOG is linked to myeloid sarcoma.