Patterns of white and gray structural abnormality associated with paediatric demyelinating disorders

Area of Science:

• Neuroimaging
• Neuroimmunology
• Pediatric Neurology

Background:

• Multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein-associated disorders (MOGAD) are central nervous system inflammatory conditions affecting youth.
• Understanding the distinct neuroanatomical impacts of MS and MOGAD in children is crucial for diagnosis and management.
• The visual pathway is frequently involved in both MS and MOGAD, making it a key area for comparative study.

Purpose of the Study:

• To compare structural brain abnormalities in pediatric MS and MOGAD patients using advanced MRI and OCT techniques.
• To identify differences and similarities in white matter integrity and cortical thickness between MS and MOGAD.
• To investigate the specific impact on the visual pathway in both conditions.

Main Methods:

• Structural MRI, Fixel-Based Analysis (FBA), and optical coherence tomography (OCT) were used to assess brain structure.
• Cortical thickness and diffusion metrics (e.g., diffusion tensor parameters) were analyzed in 18 MS patients, 14 MOGAD patients, and 26 typically developing children (TDC).
• Analyses focused on whole-brain differences and specific visual pathway metrics, including optic radiations, visual cortex, retinal nerve fibre layer (RNFL), and ganglion cell layer.

Main Results:

• Fixel-based analysis revealed widespread white matter abnormalities in MS (corticospinal tract, inferior longitudinal fasciculus, optic radiations).
• MOGAD patients showed non-lesional white matter impact predominantly in the right optic radiation.
• Cortical thinning was observed in temporal and parietal lobes (MS) and frontal, cingulate, and visual cortices (MOGAD).
• Reduced RNFL thickness in MOGAD and increased white matter integrity (TORT) in MS optic radiations suggest distinct axonal and myelin damage patterns.

Conclusions:

• Combined MRI, FBA, and OCT reveal distinct patterns of neuroanatomical damage in pediatric MS and MOGAD.
• MS is associated with more diffuse white matter compromise, whereas MOGAD shows a more focal impact, particularly in the visual pathway.
• These findings highlight the utility of multimodal neuroimaging in differentiating these conditions and understanding their specific effects on the developing brain.