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. Author manuscript; available in PMC: 2019 Jan 1.
Published in final edited form as: Magn Reson Med. 2017 Mar 31;79(1):31–40. doi: 10.1002/mrm.26683

Figure 5.

Figure 5

Spiral in versus spiral in-out subpulse simulations. (a) 0.645 ms spiral-in and spiral in-out kx trajectories. The initial linear ramp prewinder of the spiral-in trajectory is labeled. (b) Amplitude waveforms of spiral-in and spiral in-out RF subpulses for a human subject. The spiral-in waveform is zero during its prewinder, and the spiral in-out waveform is zero during the up and down ramps at either end of the pulse. (c) RMS excitation error as a function of offset frequency for spiral in and spiral in-out pulses. (d) Percent flip angle error maps at 0 Hz and 500 Hz frequency offset.