Figure 4. Excitation fidelity of static B1 shimming (i.e., single-spoke pTX pulse design) in the human brain at 9.4 T using eddy current B0 corrected single-spoke pTX pulses.

The coefficient variation values (i.e., std/mean) were calculated based on the corresponding Bloch simulations (left column), 3D GRE images normalized with respect to receive B1 (middle column) and actual flip angle imaging (right column). A nominal flip angle of 10° was used in both Bloch simulation and 3D GRE acquisition, and a higher nominal flip angle of 23° was employed in the flip angle mapping. Note that B1 shimming was not as effective as 2-spoke pTX pulse design in creating uniform excitation.