High b-value in vivo Whole-brain Diffusion MRI at 7T with a High-performance Gradient System

Motivation: Probing brain microstructure with high-b-value brain diffusion imaging was mainly performed at 3T. At higher field strength, the long echo times prohibited a significant SNR boost over 3T. At 7T, a high-performance gradient allows much shorter echo times and harvesting of the field-related signal gain. Goal(s): Determine SNR and explore feasibility of high b-value DWI. Approach: The SNR was measured in high b-value DWI at whole-body and high-performance 7T scanners. Results: The SNR improvement on the high-performance 7T is 2.76 ±0.12 and 1.73 ±0.05 compared to the whole-body 7T and high-performance Connectome 3T respectively, allowing even higher spatial resolution and higher b-value imaging. Impact: The shortcoming of 7T for high b-value diffusion MRI can be overcome when leveraging a high-performance gradient system, effectively reducing scan time 7.6-fold compared to a whole-body 7T scanner. This enables the next generation of diffusion imaging.