Diffusion Time Dependent Radial Diffusivity & Myelin qMRI in Ex Vivo Ferret Spinal Cord

Motivation: There remains a gap in knowledge surrounding what microstructural features impact similar myelin qMRI metrics. Goal(s): The goal of this work is to evaluate the relationship between a novel axon diameter surrogate and myelin qMRI metrics. Approach: Ex vivo ferret spinal cords were imaged at 15T using multiple spin echo, selective inversion recovery and diffusion tensor imaging sequences. Results: BPF was found to have a negative correlation with the axon diameter surrogate measure. MET2 derived metrics were found to have no correlation with the axon diameter surrogate measure. Impact: The diffusion time dependence of the radial diffusivity is thought to report on axon diameter towards detecting microstructural changes as a result of pathology. This work provides further evaluation of this metric and other relaxation parameters of white matter.