Characterizing axonal damage in ischemic stroke using AxCaliber MRI in high-gradient diffusion imaging

Motivation: Stroke is characterized histopathologically by axonal damage and loss. We propose and validate a novel marker for this damage following ischemic injury, to quantify changes at the microstructural level. Goal(s): We aim to develop an optimized protocol for high-gradient diffusion MRI to estimate cellular damage from ischemic stroke. Approach: We acquired diffusion MRI in patients with stroke and applied the AxCaliber methodology to estimate axon diameter and restricted volume fraction in fiber tracts of affected and contralateral hemispheres. Results: Affected hemispheres show significantly decreased restricted volume fraction in the posterior limb of the internal capsule and the corona radiata. Impact: AxCaliber-SMT applied to high-gradient diffusion MRI data offers a novel approach to probe axonal microstructural alterations following ischemic stroke and may aid in developing a sensitive imaging marker for evaluating rehabilitation strategies.