Microstructural Characterization of Network-Based Neurodegeneration in Multiple Sclerosis Using High Gradient Diffusion MRI.

Motivation: Findings of this study help clarify the microstructural substrate of network-based gray matter (GM) atrophy and improve current understanding of network concepts in multiple sclerosis (MS). Goal(s): The goal of this study was to assess network behavior of microstructural alterations in atrophy-prone GM. Approach: We leveraged high gradient diffusion MRI to probe GM at the mesoscopic scale by using the SANDI (Soma and Neurite Density Imaging) method. Results: Our results demonstrated decreased cell body density in atrophy-prone GM of MS, which correlates with clinical disability. Further, covariance of localized GM microstructural alteration suggests that neuronal loss may relate in part to network-based effects. Impact: Decreased cell body density in atrophy-prone gray matter in multiple sclerosis is correlated with clinical disability and exhibits network behavior. Findings may support future development of quantitative non-invasive methods for sensitive monitoring of disease progression to enable prompt clinical intervention.