Motivation: Most 7T brain MRI sequences require slice-select pulses with good slice profiles and correction of flip-angle (FA) inhomogeneities, which is difficult to achieve. Goal(s): We design fully optimized (FO) pulses capable of creating uniform in-slice FA excitations and box-like slice profiles using a birdcage coil alone (no pTx). Approach: We optimize the Caley-Klein parameter beta which allows control of the FA and phase inside and outside the slice. Results: FO pulses achieve ~10% FA NRMSE in-slice while creating box-like slice profile with little phase variation inside the slice and little excitation outside the slice. Impact: Slice-selective fully optimized pulses solve the FA brain homogenization problem at 7T using a birdcage coil alone (no pTx) and yield box-slice slice profiles with little phase variation inside the slice and little excitation outside.
Guérin et al. (Tue,) studied this question.