AQP4-IgG NMOSD, MOGAD, and double-seronegative NMOSD: is it possible to depict the antibody subtype using magnetic resonance imaging?

BACKGROUND: There is clinical and radiological overlap among demyelinating diseases. However, their pathophysiological mechanisms are different and carry distinct prognoses and treatment demands.

OBJECTIVE: To investigate magnetic resonance imaging (MRI) features of patients with myelin-oligodendrocyte glycoprotein associated disease (MOGAD), antibody against aquaporin-4(AQP-4)-immunoglobulin G-positive neuromyelitis optica spectrum disorder (AQP4-IgG NMOSD), and double-seronegative patients.

METHODS: A cross-sectional retrospective study was performed to analyze the topography and morphology of central nervous system (CNS) lesions. Two neuroradiologists consensually analyzed the brain, orbit, and spinal cord images.

RESULTS: In total, 68 patients were enrolled in the study (25 with AQP4-IgG-positive NMOSD, 28 with MOGAD, and 15 double-seronegative patients). There were differences in clinical presentation among the groups. The MOGAD group had less brain involvement (39.2%) than the NMOSD group ( p  = 0.002), mostly in the subcortical/juxtacortical, the midbrain, the middle cerebellar peduncle, and the cerebellum. Double-seronegative patients had more brain involvement (80%) with larger and tumefactive lesion morphology. In addition, double-seronegative patients showed the longest optic neuritis ( p  = 0.006), which was more prevalent in the intracranial optic nerve compartment. AQP4-IgG-positive NMOSD optic neuritis had a predominant optic-chiasm location, and brain lesions mainly affected hypothalamic regions and the postrema area (MOGAD versus AQP4-IgG-positive NMOSD, p = 0 .013). Furthermore, this group had more spinal cord lesions (78.3%), and bright spotty lesions were a paramount finding to differentiate it from MOGAD ( p  = 0.003).

CONCLUSION: The pooled analysis of lesion topography, morphology, and signal intensity provides critical information to help clinicians form a timely differential diagnosis.