Optimization of Inhomogeneous Magnetization Transfer Imaging on a Fully Myelinated Tract

Motivation: Among existing myelin-sensitive techniques, inhomogeneous magnetization transfer (ihMT) shows promise for optimal performance at high magnetic fields, where other methods tend to lose contrast. Yet, its tissue specificity is not fully understood. Goal(s): Validate the specificity to myelin of ihMT and optimize the acquisition parameters on a fully myelinated tract. Approach: Analyze the ihMT contrast between the rat optic nerve, grey matter, and extra-cerebral tissue across various experimental parameters, and assess ihMTR variation along the optic nerve. Results: ihMTR is a reliable measure of myelin content, as shown by the increasing ihMTR values along the optic nerve from the eye toward the brain. Impact: This study enhances our understanding of ihMT's sensitivity and specificity to myelin, paving the way toward optimized acquisition parameters and the development of a standardized protocol.