Role of conventional MRI during diagnosis, relapses and follow-up in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare and devastating inflammatory autoimmune disease of the central nervous system characterized mainly by severe attacks of myelitis, optic neuritis, brainstem (including area postrema syndrome) and/or symptomatic brain syndromes. NMOSD follows a relapsing disease course, leading to severe physical disability and potential mortality. Recent advances have been made in NMOSD including the introduction of new diagnostic criteria, identification of new biomarkers and prognosis factors, better characterization of clinical aspects, and new therapeutic approaches. Magnetic resonance imaging (MRI) of the brain and spinal cord plays a crucial role in the diagnosis of NMOSD, confirmation of attacks (especially in aquaporin-4 [AQP4]-immunoglobulin G [IgG]-negative cases), and exclusion of other differential diagnoses such as multiple sclerosis. Furthermore, MRI is essential for monitoring disease activity, detecting new asymptomatic inflammatory lesions, and assessing treatment-related side effects. In this narrative review, we discussed the role of conventional MRI during diagnosis, relapses and follow-up in NMOSD based on the most relevant published data, especially considering its utility in clinical practice.