Diffusion-weighted GRASE sequence with 3D navigator for high-resolution time-dependency measurements in the human cortical gray matter

Motivation: Oscillating gradient sequences enable diffusion measurement at short diffusion-time (td), but it suffered from low resolution and SNR on clinical systems. Goal(s): To explore the td-dependency in sophisticated structures, like cortical gray matterApproach: We proposed a 3D navigator-based 3D gradient spin-echo (GRASE) sequence for whole-brain td–dMRI at 1.5 mm isotropic resolution, which enabled us to depict the cerebral cortex. Results: We unveiled unique td-dependency patterns across cortical regions with different diffusion dispersion exponent (θ) based on the power-law, which was higher in the sensory cortex, like the occipital region, and lower in the high-order cortex like the temporal region. Impact: The high-resolution td-dMRI technique provided a new approach to characterize the cortical micro-environment and is potentially useful to capture changes due to neurological diseases.