Magnetic Resonance Imaging (MRI) Red Flags in Acute Optic Neuritis: A Practical Framework for Early Identification of Antibody-Mediated Inflammatory Optic Neuritis

Background Acute optic neuritis (ON) is most commonly associated with multiple sclerosis (MS) but may also represent antibody-mediated inflammatory optic neuropathies, including aquaporin-4 antibody – positive neuromyelitis optical spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody – associated disease (MOGAD). Early differentiation is critical because these conditions differ substantially in prognosis, recurrence risk, and treatment. Magnetic resonance imaging (MRI) plays a central role in the early evaluation of ON and is often available before serologic results.Methods A literature review was conducted in accordance with PRISMA guidelines to identify studies describing MRI features differentiating MS, AQP4-NMOSD, and MOGAD in acute ON. PubMed was searched from database inception through March 2026. After screening and eligibility assessment, 33 studies met inclusion criteria and were included in a qualitative synthesis.Results Distinct MRI patterns were identified across etiologies. Longitudinally extensive optic nerve lesions and posterior pathway involvement, including the optic chiasm and optic tract, were most strongly associated with AQP4-NMOSD. Bilateral optic neuritis, anterior optic nerve involvement, optic nerve swelling, and perineural enhancement were characteristic of MOGAD. In contrast, MS-associated ON most commonly demonstrated short, unilateral, focal optic nerve lesions without perineural involvement.Conclusion Based on these findings, we propose a practical MRI reporting framework incorporating six key elements: laterality, lesion length, segmental distribution, enhancement pattern, perineural involvement, and optic nerve swelling. Standardized reporting emphasizing these features may improve early recognition of NMOSD and MOGAD, facilitate appropriate antibody testing and subspecialty referral, and reduce delays in diagnosis and treatment.