Evaluating cortical soma radius and intra-soma and neurite fractions using ultra-high-gradient diffusion MRI data acquired at 500 mT/m

Motivation: The Connectome 2.0 MRI scanner equipped with 500 mT/m gradient strength and 600 T/m/s slew rate is expected to advance gray matter microstructural characterization within the living human brain. Goal(s): To compare Soma And Neurite Density imaging (SANDI) metrics obtained from Connectome 2.0 and 1.0. Approach: We applied SANDI model fitting to diffusion MRI data acquired from 10 healthy subjects scanned on the Connectome 2.0 and 1.0 scanners. Results: We observed lower soma radius throughout the cortex on Connectome 2.0 compared to Connectome 1.0. SANDI metrics from Connectome 2.0 exhibited considerable contrast within the sensorimotor cortex that wasn’t apparent on Connectome 1.0. Impact: The Connectome 2.0 MRI scanner with 500 mT/m gradients advances non-invasive characterization of gray matter microstructure in the living human brain and enables mapping of real differences in cyto- and myeloarchitecture with greater sensitivity compared to the original Connectome scanner.