Advancing mesoscale whole brain T2*-weighted MRI in humans at 10.5 T using motion-robust multi-echo 3D EPI and RF parallel transmission

Motivation: Last year we demonstrated at 10.5 T the utility of motion-robust multi-echo GRE imaging for mesoscale T2*-weighted (T2*w) whole brain MRI with 0.5-mm isotropic resolution. Goal(s): To push the limit of mesoscale T2*w multi-echo whole brain MRI by combining motion-robust 3D EPI and parallel transmission (pTx). Approach: Whole brain three-echo EPI at 0.4-mm isotropic resolution was performed using a custom 16-channel transmit 80-channel receive RF array with a scan time of ~10 min. Tailored pTx pulses were designed for uniform water excitation. Results: Our new mesoscale image acquisition eliminated RF artifacts observed before, allowing intricate anatomical details to be visualized across the brain. Impact: Armed with rapid motion-robust 3D EPI and parallel transmission, the presented new multi-echo T2*-weighted imaging strategy will benefit many neuroscience applications, especially those aiming to investigate fine scale anatomy in humans at ultrahigh field.