Figure 1.

B1 homogeneity data acquisition and image postprocessing. The cardiac modulus images (A and D) and B1 maps (B and E) in the horizontal long axis were acquired with single source (A and B) and dual source (D and E) radiofrequency (RF) transmission. The region of interest was drawn manually on the modulus image (A and D) and copied to corresponding B1 map (B and E). Improved B1 homogeneity was found visually in B1 maps with dual source RF transmission (E) compared with single source RF transmission (B). The distribution of achieved percentage of nominal flip angle (FA) with dual source RF transmission (F) was more concentrated and homogeneous than that with single source RF transmission (C). Besides, the mean percentage of FA was higher with dual source RF transmission (F). FA = flip angle, HLA = horizontal long axis, RF = radiofrequency, ROI = region of interest.