Safety excitation efficiency of MRI 300MHz dualrow transmit arrays

We investigated how performance trade-off depends on dual-row transmit array geometry, position of a head inside the array and array tuning condition. A clear winner was not found. For overlapped arrays, different tuning conditions resulted in larger peak-to-peak variation for CP excitation, but B_1+v decrease was as a bit less for excitations that minimized IB_1+v as compared with nonoverlapped arrays. For non-overlapped array the safety excitation efficiency was better if the distance between the crown of the head and the end of the array was small.