Time Optimal VERSE Excitation for 3D Balanced SSFP Imaging

Figure 3. Coronal (top) and axial (bottom) views from a 3D acquisiton slightly above the heart. Images have 2x2x3 mm resolution. The coronal image shows the 4cm, TB=10 slab profile in vivo. The contrast is consistent across the slab, indicating a flat slab profile. The black level is 0 for these images. Introduction: Balanced steady-state free precession (SSFP) imaging (TrueFISP, FIESTA, balanced-FFE) is a rapid imaging method that provides good tissue contrast with high SNR efficiency. However, maintaining high SNR efficiency requires a high readout duty cycle. This is often achieved by shortening the excitation pulse, which compromises the 3D slab profile. A mediocre slab profile results in fewer useful slices, both because of through-slab aliasing and diminished contrast due to reduced flip angle in the transition band. This is especially true when a thin slab is used to limit the field of view. In this work, we apply variable-rate selective excitation (VERSE) to design short-duration pulses with sharp slab profiles that are appropriate for 3D balanced SSFP imaging.