Free-water corrected Diffusion Kurtosis Imaging exhibits modified age-related trajectories of the measures in the brain white matter

Diffusion kurtosis imaging (DKI) allows quantifying Gaussian and non-Gaussian effects in diffusion MRI signal and has already proved its relevance, including assessing age-related brain alterations. Hitherto, the standard DKI follows a single-component signal representation with no explicitly defined free-water factor that might lead to a reduced specificity of tensor-based measures. This work demonstrates the free-water corrections to the DKI and revisits the variations in the metrics across the adult lifespan. Our study shows a significant reduction in variability and dynamics of the kurtosis fractional anisotropy and the preservation of the status quo in the mean kurtosis tensor with age.