Coping with Off-Resonance Effects and Gradient Imperfections in Parallel Transmission Experiments
نویسندگان
چکیده
Introduction: Parallel transmission has proven to provide good results for spatially selective excitation with reasonable RF-pulse durations [1]. For best spatial definition, exact matching of RF-pulses with a simultaneously played out gradient waveform, which defines a k-space position for every point in time, is crucial. However off-resonance effects and gradient imperfections may lead to distortions in the excited pattern. In this study several approaches are presented and compared which allow the mitigation of the impact of such inaccuracies by measuring and pre-calibrating the k-space trajectory and by basing the RF pulse calculation on such measured data.
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