FIG. 6.

Three-plane view of the whole-brain EPI acquisitions with axial slices in three subjects, acquired at factor-2 slice acceleration with MB-RF and SMS-pTX excitations. Data acquired without FOV-shift between simultaneous slices are shown in panel (A); repeating the same experiment with blipped-CAIPIRINHA (FOV/2-shift between slices; panel (B)) did not visibly affect image quality, which demonstrates the suitability of the dual-row geometry to separate two axial slices. Overall apparent image quality between the MB-RF and SMS-pTX methods is comparable, but signal reductions and discontinuities in image intensity can be observed in the transition areas between the two slice groups. This is attributable to the reduced B₁⁺ especially near interface of the two coil rows and also the step function in B₁⁺ profile, as is evident from the maps in panel (C), which show the relative signal reduction of SMS-pTX vs. MB-RF (for the case without CAIPI).