Fig. 6.

Axial and sagittal views through the center of the heart (depicted in red) showing the B₁⁺ efficiency maps (B₁⁺/√1 kW) using the a self-grounded bow-tie antenna building block; b bow-tie antenna building block; and c) the fractionated dipole antenna RF array configurations at 7.0 T (baseline, BL) and 14.0 T (same channel count, SCC, double channel count, DCC). Dynamic pTx was performed with tailored kT-points, using a series of RF sub-pulses and gradient blips to achieve a homogeneous flip angle (FA) within the 3D ROI targeting the heart. For the optimization, a nominal FA of 10° was targeted in the heart ROI by using 4 and 8 kT-points, with a total pulse duration of 0.96 ms and 1.92 ms, respectively. The FA maps of the pulse design were scaled into B₁⁺ efficiency maps