Neuroimaging of Neuromyelitis Optica Spectrum Disorder

This article reviews the key imaging features of neuromyelitis optica spectrum disorder (NMOSD), an autoimmune astrocytopathy targeting the optic nerves and spinal cord. Accurate differentiation from mimics like multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is crucial due to differences in treatment and prognosis. The hallmark radiologic signs of NMOSD are described, including longitudinally extensive transverse myelitis spanning three or more vertebral segments and characteristic brain lesions in aquaporin-4–rich areas, such as the periependymal regions of the third and fourth ventricles and the area postrema. In contrast to MS, NMOSD lesions rarely involve the cortex and have a low incidence of the central vein sign. NMOSD findings are compared with those of MOGAD and acute disseminated encephalomyelitis. Clinical imagers can use this practical, image-rich, and evidence-based review to confidently recognize NMOSD and distinguish it from its primary differential diagnoses.