Brain MRI findings of three NMOSD patients and three MS patients. FLAIR MRI shows a (A) continuous linear ependymal lesion along the ventricle in a 29-year-old woman with NMOSD; (B) symmetrical hypothalamic lesion in an 18-year-old girl with NMOSD; and (C) typical symmetrical and continuous ependymal lesion around the periaqueductal area in a 17-year-old girl with NMOSD. T2-weighted image shows (D) ependymal dot lesions beside the ventricle in a 32-year-old woman with MS. FLAIR MRI shows (E) an asymmetric hypothalamic lesion in a 26-year-old woman with MS and (F) asymmetric ependymal dot lesions along the periaqueductal gray in a 37-year-old woman with MS. NMOSD: neuromyelitis optica spectrum disorder; MS: multiple sclerosis; FLAIR: fluid attenuated inversion recovery; MRI: magnetic resonance imaging. NMOSD: neuromyelitis optica spectrum disorder.