Electrodynamic constraints on minimum SAR in parallel excitation

By making use of multiple independently driven transmit coils, parallel transmission enables acceleration of multidimensional excitation pulses, widening the range of clinical applications for which they can be employed [1,2]. Transmission of tailored radiofrequency (RF) waveforms with the individual elements of a transmit coil array was also shown to provide better management of RF power deposition [2], which is critical for MR imaging at high magnetic field strength. As such applications are explored further, it will be important to investigate the intrinsic constraints of the technique. In the case of parallel imaging, it has been shown that there is a