Inferring conduction velocity properties from qMRI-derived Structural Myelin Integrity (SMI) using qMT and MWF

Motivation: Myelin structural integrity is crucial for securing neural signaling. We aim to distinguish myelin content from myelin organization, addressing the need for more precise structure-to-function-related diagnostic tools. Goal(s): To assess myelin water imaging (MWI) and quantitative magnetization transfer (qMT) sensitivity to myelin loosening and remyelination, and introduce structural myelin integrity (SMI) as a conduction velocity integrity proxy. Approach: We used two rat models based on demyelinating injections and postmortem degeneration. Results: MWI is sensitive to myelin organization changes, while qMT reflects macromolecular content. SMI, combining both, may better reflect conduction velocity, showing remyelination trends aligning with known signal conduction velocity recovery patterns. Impact: We introduce a new myelin metric that directly links myelin's structural properties to signal conduction velocity, addressing the limitations of MWF and qMT. It opens new research opportunities into myelin dynamics related to its functional properties.