bSSFP Phase Contrast (PC-SSFP) at 0.55T for Aortic Flow

Motivation: Aortic flow imaging at 0.55T has limited SNR, especially in diastolic phases, which can limit the accuracy of flow and regurgitant fraction measurements. Goal(s): Our goal was to improve the SNR of phase contrast images at 0.55T using a bSSFP readout and maintain accurate flow quantification. Approach: We developed a through-plane phase contrast sequence with bSSFP readout and tested it in phantoms and healthy volunteers. Results: Significantly improved SNR (25.5±9.6 vs 8.2±2.9, p<0.001) and accuracy of velocities measurement were demonstrated in phantom. Accurate flow and constant high SNR were measured using our method in 8 subjects, for both breath-hold and free-breathing cases. Impact: Our proposed phase contrast with bSSFP readout can reliably evaluate aortic flow at 0.55T with higher SNR and VNR leading to more accurate quantification compared to conventional GRE based phase contrast method.