Figure 7:
Comparison of the distortion between 2nd order SH global shimming and dynamic shimming using a 31-channel custom multi-coil shim array. Column 1 shows a reference MPRAGE acquisition where the brain outline was segmented for reference using BET and overlaid in red. Columns 2 through 5 show EPI acquisitions with the same acquisition parameters except for the shimming procedure and phase encoding direction. Columns 2 and 3 show global shimming using 2nd order spherical harmonics in the AP and PA phase encoding direction respectively. Column 4 and 5 show dynamic shimming using Shimming Toolbox and the multi-coil shim array with phase encoding direction of AP and PA respectively. Slice numbers: A: 16, B: 24, C: 32, D: 40.