Age-Related Alterations in Tissue Microstructure along perforant pathway of Hippocampus and the Tract Template Development

Motivation: Quantifying microstructural alterations with age in the perforant pathway facilitates the understanding of mechanisms in aging and neurodegeneration. Goal(s): We investigated age-related changes along perforant pathway of hippocampus and established a hippocampal tract template. Approach: We acquired diffusion MRI (dMRI) data from 72 participants (19-85 year-old) on high-gradient performance Connectome MRI scanner. dMRI tract-based analysis revealed age-related alterations of diffusion metrics (DKI, SANDI) along perforant pathway. Results: Along perforant pathway, FA decreased with age in WM, intra-neurite volume fraction decreased with age in WM and entorhinal cortex, and extracellular volume fraction decreased with age in dentate gyrus and entorhinal cortex (p<0.05). Impact: We observed age-related alterations in tissue microstructure along the perforant pathway of hippocampus using high-gradient performance diffusion MRI. We built a hippocampal tract template using data of young subjects, offering a practical tool to investigate neurodegenerative diseases affecting hippocampal tracts.