Background: Although neuromyelitis optica has been traditionally regarded as a disease without brain involvement, brain abnormalities are not uncommon in patients with neuromyelitis optica-related disorders.Methods: We aimed to characterize the brain magnetic resonance imaging (MRI) abnormalities in neuromyelitis optica spectrum disorder patients who are seropositive for anti-aquaporin-4 autoantibody (AQP4 Ab). Of 236 consecutive patients with inflammatory demyelinating central nervous system diseases, we retrospectively analyzed MRI characteristics of 78 patients who were seropositive for AQP4 Ab.Results: For an average observational period of 6.3 years, 62 patients (79%) had brain lesions on MRI