Radiological differentiation of optic neuritis with myelin oligodendrocyte glycoprotein antibodies, aquaporin-4 antibodies, and multiple sclerosis

TLDR

Recognizing the underlying cause of optic neuritis is critical for guiding treatment and preserving vision. The study aimed to delineate the radiological characteristics of first‑episode demyelinating optic neuritis. Blinded radiological review was conducted on 50 patients with first‑episode MOG‑associated, AQP4‑associated, MS‑associated, and unclassified optic neuritis. Compared with MS‑associated optic neuritis, MOG‑ and AQP4‑associated cases were more often bilateral and longitudinally extensive, with MOG‑ON showing anterior optic‑pathway involvement and optic‑nerve‑head swelling, AQP4‑ON exhibiting posterior pathway, chiasmal, and optic‑tract involvement, and a combination of absent brain MRI abnormalities and higher lesion‑extent scores effectively distinguishing autoantibody‑associated ON from MS, while AQP4‑ON was linked to more severe visual loss.

Abstract

Background: Recognizing the cause of optic neuritis (ON) affects treatment decisions and visual outcomes. Objective: We aimed to define radiological features of first-episode demyelinating ON. Methods: We performed blinded radiological assessment of 50 patients presenting with first-episode myelin oligodendrocyte glycoprotein (MOG) antibody-associated ON (MOG-ON; n=19), aquaporin-4 (AQP4) antibody-associated ON (AQP4-ON; n=11), multiple sclerosis (MS)-associated ON (MS-ON; n=13), and unclassified ON ( n=7). Results: Bilateral involvement was more common in MOG-ON and AQP4-ON than MS-ON (84% vs. 82% vs. 23%), optic nerve head swelling was more common in MOG-ON (53% vs. 9% vs. 0%), chiasmal involvement was more common in AQP4-ON (5% vs. 64% vs. 15%), and bilateral optic tract involvement was more common in AQP4-ON (0% vs. 45% vs. 0%). Retrobulbar involvement was more common in MOG-ON, whereas intracranial involvement was more common in AQP4-ON. MOG-ON and AQP4-ON had longer lesion lengths than MS-ON. The combination of two predictors, the absence of magnetic resonance imaging brain abnormalities and a higher lesion extent score, showed a good ability to discriminate between an autoantibody-associated ON (MOG or AQP4) and MS. AQP4-ON more frequently had severe and sustained visual impairment. Conclusion: MOG-ON and AQP4-ON are more commonly bilateral and longitudinally extensive. MOG-ON tends to involve the anterior optic pathway, whereas AQP4-ON the posterior optic pathway.