Figure 5.

To demonstrate the effect of the TR-durations in multiple-TR bSSFP (N = 4, TR₁ = TR₂, TR₃ = TR₄), we can keep either TR₁ (a) or the total TR (2*[TR₁+TR₃]) constant (b), and vary τ = TR₃/TR₁. In the first case, TR₃ and the total TR are shortened by decreasing τ because TR₁ is fixed. However, the pass-band width has a very weak dependence on τ for fixed TR₁, if it is defined as the full width at half maximum. In contrast, TR₁ is lengthened for smaller τ and a fixed total TR, effectively shrinking the pass-band. In both a and b, τ = 0.5 (marked with the ticks on the vertical axis) creates a stop-band (marked with the dashed white line) that has 1.67 times the width of the corresponding pass-band (marked with the dashed black line). Finally, τ = 1 produces a regular bSSFP response as expected.