Figure 4

Illustration of flip angle strategies throughout the cardiac cycle. The bold, horizontal lines indicate the constant flip angle strategies where the same flip angle is applied throughout the cardiac cycle. The ramped flip angle strategies are indicated by the dashed lines and were calculated as described by Stuber et al. [13]. Notice that the ramped flip angle strategies start at low values and increase throughout the cardiac cycle. They are defined by their last flip angle (e.g. the red dashed line is the ramped flip angle strategy that ends at 15°). The ramped flip angle strategies in this illustration were calculated by using 17 ms repetition time, 1000 ms T1 relaxation constant, and 20 cardiac phases (40 repetition times). Typical values of myocardial T1 for healthy volunteers at 3T and 1.5T have been found [21] and were used in this illustration.