Patch Antenna in Comparison to and in Combination with a Volume Coil for Excitation at 7T: Whole-Brain B1 Shimming and Consequent SAR

Chien-ping Kao¹, Zhipeng Cao¹, Sukhoon Oh¹, Yeun Chul Ryu¹, Christopher M. Collins¹

Here we compare the homogeneity in whole-brain excitation that can be achieved with two adjustable transmit channels used to drive a patch antenna and to drive a body array with elements combined as to form two orthogonal mode 1 field patterns. Optimal whole-brain homogeneity achievable with B1 shimming and the resulting SAR is examined for the two approaches separately and combined. Combining the patch and the body array results in appreciable better achievable whole-brain homogeneity with significantly lower average and maximum local SAR than possible with either the patch antenna or body coil alone.