RF transmit performance comparison for several MRI head arrays at 300 MHz

We numerically investigated several transmit arrays used for magnetic resonance imaging (MRI) at 300MHz. The array was loaded by a typical human head model. For each array two independent optimization strategies were applied to flne-tune the circuit-level array performance. For excitation in the circular polarization mode, the design of the head array element | whether loop, strip line, or locally shielded microstrip | had no signiflcant impact on entire brain RF inhomogeneity, transmit and safety excitation e-ciencies for the entire brain, although magnetic fleld and SAR proflles vary with element design. Delivery of the maximal fraction of transmit power to the brain ensured the best transmit performance.