"MY Way" a New Construction Technique for Broadband Slice-Selective Refocusing Pulses

James B. Murdoch¹

High-bandwidth slice-selective refocusing pulses are important for proton spectroscopy at 3T and above, but they are not easy to construct. Previously it has been proposed to combine a self-refocused 90 excitation pulse with a time-reversed version of itself to create a suitably spin-flipping 180 waveform. However, the 90 pulse need not be wholly slice-selective: M_X and M_Z can vary outside the desired slice width so long as M_Y≈0. Both AM and PM excitation pulses have therefore been optimized for the proper M_Y response and then combined to spawn new refocusing pulses (with a PM second-component phase flip for overall antisymmetry).