Development of GRASE Pulse Sequence with larger field of view for Mesoscale functional MRI on the Next Generation (NexGen) 7T scanner

Motivation: Mesoscale fMRI using GRASE has been shown to be less susceptible to pial bias, but is hampered by small coverage and lower SNR then GE BOLD. Goal(s): Acceleration methods incorporating random sampling have been shown to increase coverage and boost SNR, but are still somewhat limited by hardware. Approach: Combining accelerated GRASE with random sampling with the improved hardware of the NexGen 7T allows FOV to be expanded and resolution to be increased. Results: High-resolution fMRI in visual and sensorimotor cortices demonstrates that accelerated GRASE can be used for mesoscale functional imaging. Impact: The advanced hardware of the NexGen 7T combined with accelerated 3D GRASE incorporating random sampling allows for increases in coverage and resolution to enable mesoscale imaging. GRASE images show decreased pial vein and brain surface layer bias than GE-EPI