Compensation of multi‐dimensional selective excitation pulses using measured k‐space trajectories

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Abstract
Multidimensional spatially selective excitation pulses rely on the accuracy of gradient waveforms to achieve desired excitation volumes. Unfortunately, the high gradient slew‐rates and magnitudes required by these pulses often lead to distortion of the waveforms produced by imaging systems resulting in poor selection profiles. In this paper, a k‐space calibration procedure, used to determine the actual trajectory produced by the scanner's field gradients, is extended to two spatial dimensions. This measured information is then incorporated in a selective excitation design technique for correcting the RF pulse envelopes to compensate for gradient waveform induced distortion of the excitation volumes.