SAR Sensitivity to Phase AndSAR Sensitivity to Phase and Amplitude Perturbations When Utilizing Parallel Transmission

Martijn Anton Cloos¹, Michel Luong², Guillaume Ferrand², Alexis Amadon¹, Dennis Le Bihan¹, Nicolas Boulant¹

When using parallel transmission at high field, it is well established that high local specific absorption rate (SAR) values can occur. So far, no reports have been made regarding the behavior of transmit-SENSE pulses with regard to amplitude and phase perturbations. In this work, we investigated the behavior of the local SAR regarding perturbed spoke k-space trajectory-based excitation pulses designed using simulated B1-maps. Results indicate that although substantial variations can occur the local SAR may be considered relatively robust and remains far below the local SAR obtained with the worst-case scenario.