Parallel-transmit pulses are commonly used to improve B1+-homogeneity at higher field strengths, while local-SAR constraints are applied to ensure safety. However, patient motion may become unavoidable with longer scans or less cooperative patients, and motion may affect B1+-homogeneity and local-SAR. We investigated the effect of all 6 degrees-of-freedom of head motion on B1+-homogeneity and local-SAR for parallel-transmit multi-spoke pulses using simulations. We observed more than a 2-fold increase in local-SAR due to motion for some pulses. We also investigated the changes in B1+-homogeneity of spokes pulses using in-vivo B1+-maps and showed regional variations between 12%-22% in the excitation profile.
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