Parallel transmit spatial-spectral pulse design with specific absorption rate control for water excitation: validation in humans at 7 Tesla

Motivation: Last year we demonstrated the utility of our new parallel transmit spatial-spectral pulse design for robust water excitation, but only using Bloch simulations without experimental proof. Goal(s): Our goal here was to validate our method via phantom and human scans at 7 Tesla. Approach: We validated our design method by collecting 3D GRE data in a water-fat phantom and in the human brain. All data were obtained on a Siemens Terra using the commercial Nova 8-channel transmit coil. Results: Our method outperformed existing approaches, producing uniform water excitation across the whole brain with nearly complete fat suppression even in the challenging areas. Impact: Validated in humans at 7 Tesla, our design method provides an effective solution for volumetric uniform water excitation, eliminating the need for additional fat saturation and holding a promise to many applications including high-resolution functional MRI at ultrahigh field.