Fig. 4.

(A) B₀ maps acquired in vivo without DC currents in four representative slices. The B₀ RMSE in the anterior half of the brain is shown at the top. (B) B₀ field generated by the RF/shim coils with optimal DC currents (i.e., sum of the basis B₀ maps weighted by the optimal DC currents). The average and maximum DC current amplitudes applied in the RF/shim coils are shown at the top. (C) B₀ maps with optimal DC currents predicted from the shim optimization (i.e., sum of (A) and (B)). (D) B₀ maps acquired in vivo with optimal DC currents. The B₀ RMSE in the anterior half of the brain and percent reduction with respect to (A) are shown at the top.