Comparison on the Traveling Wave Excitation and the Conventional Excitation

Bei Zhang¹, Daniel K. Sodickson¹, Riccardo Lattanzi¹, Qi Duan¹, Ryan Brown¹, Bernd Stoeckel², Graham Wiggins¹

This abstract uses the finite difference time domain (FDTD) method to simulate a stepped-diameter traveling wave system and TEM resonator system loaded with the same body model, and compare the simulation results of these two systems in terms of B1 mapping, SAR distribution and system efficiency. The result shows that the traveling wave system and conventional TEM body coil in 7T are simulated to compare in terms of B1 mapping, SAR distribution and system efficiency. Both systems show strong B1+ inhomogeneities in the torso, though these could in principle be mitigated with a parallel multi-port TEM excitation. The combination of strong attenuation of the traveling wave and high SAR in tissues near the patch antenna make the TWS less suitable for whole body imaging than a local standing wave transmitter such as the TEM.