Figure 6.

The ratio of actual to nominal flip angle as simulated on the 20 × 21 $B_1^{+}-\mathrm{\Delta }{B}_0$ optimization grid (columns 1, 3, and 5) along with RF amplitude and phase modulation waveforms (columns 2, 4, and 6). Columns 1 and 2 are maximum-bandwidth block pulses; columns 3 and 4 are BIR-4 pulses (ΔT = 4.096 ms); columns 5 and 6 are select optimized composite pulses (ΔT = 4.096 ms); rows correspond to different nominal flip angles (indicated at left). Maps reflect the on-resonance $B_1^{+}-\text{insensitivity}$ of BIR-4 and optimized pulses while optimized pulses result in significantly improved off-resonance behavior.