Neurite Microstructure Characterization in the Mouse Brain Using Relaxation-Diffusion MRI

Motivation: Relaxation-diffusion MRI (rdMRI) measurements provide novel insights into tissue microstructural characteristics. Goal(s): This study aims to apply rdMRI to investigate the age-related microstructural changes in the mouse brain. Approach: We acquired rdMRI data from in vivo mouse brains across five age groups using a 9.4T MRI scanner. Relaxation-regressed diffusion signals were calculated to extract quantitative diffusion metrics. Results: Quantitative rdMRI parameters revealed significant age-dependent microstructural differences in the cortex (CX), hippocampus (HC), and corpus callosum (CC). Moreover, the rdMRI technique exhibited sensitivity to alterations in tissue microstructure that cannot be observed by standard single-TE dMRI. Impact: This study demonstrated the feasibility of using rdMRI to observe brain microstructural changes during development, potentially offering diagnostic markers for age-related diseases.