What is the optimal myelin marker? Evidence from multi-contrast MRI, histology, and deep learning

Motivation: Deep neural networks trained with MRI and myelin histology data offer enhanced sensitivity and specificity compared to conventional MRI markers, yet their inner workings remain unknown. Goal(s): To elucidate the relationships between MRI and myelin histology. Approach: We mapped multi-parametric MRI data of developing mouse brains and their myelin content onto a 3D manifold after dimension reduction and defined the relationships between MRI and myelin signals in a piecewise fashion. Results: Our findings revealed how the relationships between multiple MRI parameters and tissue myelin content evolved throughout brain development. Impact: We have developed a novel data-driven approach to characterize the complex relationship between MRI parameters and myelin. The results suggest that multi-parametric MRI is necessary for accurate myelin mapping.