Medical Biophysics, University of Toronto, Toronto, ON, Canada.
Translational Medicine, Hospital for Sick Children, Toronto, ON, Canada.
J Cardiovasc Magn Reson. 2018 Nov 29;20(1):77. doi: 10.1186/s12968-018-0498-z.
To image multidimensional flow in fetuses using golden-angle radial phase contrast cardiovascular magnetic resonance (PC-CMR) with motion correction and retrospective gating.
A novel PC-CMR method was developed using an ungated golden-angle radial acquisition with continuously incremented velocity encoding. Healthy subjects (n = 5, 27 ± 3 years, males) and pregnant females (n = 5, 34 ± 2 weeks gestation) were imaged at 3 T using the proposed sequence. Real-time reconstructions were first performed for retrospective motion correction and cardiac gating (using metric optimized gating, MOG). CINE reconstructions of multidimensional flow were then performed using the corrected and gated data.
In adults, flows obtained using the proposed method agreed strongly with those obtained using a conventionally gated Cartesian acquisition. Across the five adults, bias and limits of agreement were - 1.0 cm/s and [- 5.1, 3.2] cm/s for mean velocities and - 1.1 cm/s and [- 6.5, 4.3] cm/s for peak velocities. Temporal correlation between corresponding waveforms was also high (R~ 0.98). Calculated timing errors between MOG and pulse-gating RR intervals were low (~ 20 ms). First insights into multidimensional fetal blood flows were achieved. Inter-subject consistency in fetal descending aortic flows (n = 3) was strong with an average velocity of 27.1 ± 0.4 cm/s, peak systolic velocity of 70.0 ± 1.8 cm/s and an intra-class correlation coefficient of 0.95 between the velocity waveforms. In one fetal case, high flow waveform reproducibility was demonstrated in the ascending aorta (R = 0.97) and main pulmonary artery (R = 0.99).
Multidimensional PC-CMR of fetal flow was developed and validated, incorporating retrospective motion compensation and cardiac gating. Using this method, the first quantification and visualization of multidimensional fetal blood flow was achieved using CMR.
使用带运动校正和回顾性门控的黄金角度径向相位对比心血管磁共振（PC-CMR）对胎儿进行多维流动成像。
使用非门控黄金角度径向采集和连续递增速度编码开发了一种新的 PC-CMR 方法。在 3T 上，使用所提出的序列对健康受试者（n=5，27±3 岁，男性）和孕妇（n=5，34±2 周妊娠）进行成像。首先进行实时重建，以进行回顾性运动校正和心脏门控（使用度量优化门控，MOG）。然后使用校正和门控数据进行多维流动的 CINE 重建。
在成人中，使用所提出的方法获得的流动与使用传统门控笛卡尔采集获得的流动非常吻合。在五名成年人中，平均速度的偏差和一致性界限为 -1.0cm/s 和 [-5.1, 3.2]cm/s，峰值速度的偏差和一致性界限为 -1.1cm/s 和 [-6.5, 4.3]cm/s。对应波形之间的时间相关性也很高（R~0.98）。MOG 和脉冲门控 RR 间隔之间计算的定时误差较低（约 20ms）。首次获得了多维胎儿血流的见解。在三个胎儿降主动脉血流中，受试者间一致性很强，平均速度为 27.1±0.4cm/s，收缩期峰值速度为 70.0±1.8cm/s，速度波形的组内相关系数为 0.95。在一个胎儿病例中，在升主动脉（R=0.97）和主肺动脉（R=0.99）中证明了高血流波形重现性。
开发并验证了胎儿血流的多维 PC-CMR，结合了回顾性运动补偿和心脏门控。使用该方法，首次使用 CMR 实现了多维胎儿血流的定量和可视化。
