Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705-2275, USA.
J Magn Reson Imaging. 2012 Jun;35(6):1462-71. doi: 10.1002/jmri.23588. Epub 2012 Jan 26.
To validate a novel approach for accelerated four-dimensional phase contrast MR imaging (4D PC-MRI) with an extended range of velocity sensitivity.
4D PC-MRI data were acquired with a radially undersampled trajectory (PC-VIPR). A dual V(enc) (dV(enc) ) processing algorithm was implemented to investigate the potential for scan time savings while providing an improved velocity-to-noise ratio. Flow and velocity measurements were compared with a flow pump, conventional 2D PC MR, and single V(enc) 4D PC-MRI in the chest of 10 volunteers.
Phantom measurements showed excellent agreement between accelerated dV(enc) 4D PC-MRI and the pump flow rate (R(2) ≥ 0.97) with a three-fold increase in measured velocity-to-noise ratio (VNR) and a 5% increase in scan time. In volunteers, reasonable agreement was found when combining 100% of data acquired with V(enc) = 80 cm/s and 25% of the high V(enc) data, providing the VNR of a 80 cm/s acquisition with a wider velocity range of 160 cm/s at the expense of a 25% longer scan.
Accelerated dual V(enc) 4D PC-MRI was demonstrated in vitro and in vivo. This acquisition scheme is well suited for vascular territories with wide ranges of flow velocities such as congenital heart disease, the hepatic vasculature, and others.
验证一种新的方法，用于加速具有扩展速度灵敏度范围的四维相位对比磁共振成像（4D PC-MRI）。
使用径向欠采样轨迹（PC-VIPR）采集 4D PC-MRI 数据。实施双 V(enc)（dV(enc)）处理算法，以研究在提供改进的速度-噪声比的同时节省扫描时间的潜力。在 10 名志愿者的胸部中，将流量和速度测量值与流量泵、常规 2D PC MR 和单 V(enc) 4D PC-MRI 进行比较。
在胸部中，对志愿者进行了研究。在体模测量中，加速的 dV(enc) 4D PC-MRI 与泵流量之间显示出极好的一致性（R(2)≥0.97），测量的速度-噪声比（VNR）提高了三倍，扫描时间增加了 5%。当将 V(enc) = 80 cm/s 时采集的 100%数据与 V(enc) = 160 cm/s 时采集的 25%数据相结合时，发现了合理的一致性，从而在 160 cm/s 的更宽速度范围内提供了 80 cm/s 采集的 VNR，而扫描时间延长了 25%。
在体内外都证明了加速的双 V(enc) 4D PC-MRI。这种采集方案非常适合血流速度范围较宽的血管区域，例如先天性心脏病、肝血管等。
