Fig 2.

B0, B1+, and SD maps of one volunteer. Five sessions of B0 and B1+ maps are shown for FB and BH, and the SD maps calculated from those five maps are also shown. The window level and width of these images are the same in B0, B1+, and each SD maps, respectively. Note that B1+ maps are created for each of two channels. B0 maps vary across five sessions in FB (top row), while those are constant in BH (second row). B1+ maps of each channel also show variation across five sessions in FB (third and fifth row), and those maps are constant in BH (fourth and sixth row). As a result, values of SD maps are higher in FB than in BH, both for B0 and B1+ maps, indicating that reproducibility is better in BH than in FB. FB, free-breathing; BH, breath-holding; SD, standard deviation.