B1+ shimming with SAR reduction in high-field MRI

In high-field magnetic resonance imaging systems, parallel excitation with a multi-channel transmitter and receiver has been widely investigated to mitigate inhomogeneity. Multi-channel RF coils employed in the parallel imaging may alleviate the non-uniformity in the field and each element can be independently controlled by adjusting the phase and amplitude of the excitation. In this paper, convex optimization for each coil elements to homogenize and to reduce E fields is proposed. Improved homogeneity and reduced specific absorption rate over the whole field of view is achieved.