Age-related decline in diffusion anisotropy of subarachnoid space using higher b-values

Motivation: A recent study reported an age-related decline in diffusion anisotropy in subarachnoid space, where the diffusion MRI was measured using a conventional b-value of 1000. Using higher b-values may help identify contributions of the tissue microstructure in subarachnoid space to aging. Goal(s): We aimed to investigate age-related changes in diffusion anisotropy within subarachnoid space using higher b-values. Approach: We measured diffusion parameters using higher b-values (1000, 2000, and 3000) and observed their associations with age. Results: Using higher b-values, we observed stronger associations between subarachnoid space diffusion anisotropy and age, with higher correlation coefficients and lower p-values. Impact: The age-related decline in diffusion anisotropy of subarachnoid space was stronger using higher b-values. This suggests that age-related decline in diffusion anisotropy may be influenced by the tissue microstructure in subarachnoid space.