In-vivo evidence for cell body loss in cortical lesions in people with multiple sclerosis

Motivation: Cortical lesions are linked to irreversible cortical atrophy as well as cognitive impairment in multiple sclerosis. High-gradient diffusion MRI is sensitive to the microstructural substrate of neurodegeneration in multiple sclerosis. Goal(s): To identify in-vivo patterns of cell body density alterations, quantified by advanced diffusion MRI, in and surrounding focal cortical demyelination in people with multiple sclerosis. Approach: The intra-cellular signal fraction, reflective of cell body density, was compared between cortical lesions, perilesional and normal-appearing cortex. Results: Multiple sclerosis-related decreases in intra-cellular signal fraction were seen in cortical lesions compared to perilesional and normal-appearing cortex. Impact: High-gradient diffusion MRI has the potential to identify cortical cell body loss in-vivo, potentially attributable to focal demyelination, relevant for cognition.