Diffusion MRI acquisition methods for post-mortem imaging on a 10.5 T whole-body human MRI scanner

Motivation: High-quality post-mortem diffusion MRI + microscopy datasets acquired in the same brain enable novel, cross-scale neuroanatomical investigations. Goal(s): Identify a sequence that maximises SNR-efficiency and diffusion contrast in a post-mortem macaque brain using a 10.5 T whole-body human MRI scanner. Approach: Theoretical SNR-efficiency comparisons were performed between the diffusion-weighted spin-echo (DW-SE), stimulated-echo (DW-STE) and steady-state free precession (DW-SSFP) sequence. We performed a pilot investigation using the leading method in a post-mortem macaque brain. Results: DW-SSFP predicted the highest SNR-efficiency across the target b-value range. Acquired DW-SSFP data (0.4 mm isotropic) demonstrated high-SNR diffusivity estimates without geometric distortions, resolving multiple-fibre populations and long-range tracts. Impact: This research investigates acquisition methods to obtain high-quality post-mortem diffusion MRI datasets using a 10.5 T whole-body human MRI scanner. Data acquired using the described methodology provide detailed neuroanatomical information, informing future brain connectivity and in vivo investigations.