Fig. 2.

Spatially normalized and averaged R1 maps of healthy volunteers with different corrections for RF transmit field inhomogeneities. (a) R1 map corrected with UNICORT (R1_UNICORT; left column), uncorrected apparent R1 map (R1_app; center column), R1 map corrected with measured B1⁺ map (R1_m; right column). In the uncorrected map, the spuriously increased R1 values in the center of the brain due to RF inhomogeneities can be well seen (red arrow). (b) Percent differences in R1 values between the B1⁺ map corrected R1 map (R1_m) and the UNICORT (R1_UNICORT; left column) or uncorrected apparent (R1_app; right column) R1 map, respectively. In the difference between R1_app and R1_m the typical asymmetric RF inhomogeneities can be appreciated (green arrow).