Research & Development Group, Hitachi, Ltd., Tokyo, Japan.
Research & Development Group, Hitachi, Ltd., Tokyo, Japan.
Ultrasound Med Biol. 2019 Jul;45(7):1663-1674. doi: 10.1016/j.ultrasmedbio.2019.02.014. Epub 2019 Apr 16.
A vascular vector flow mapping (VFM) method visualizes 2-D cardiac flow dynamics by estimating the radial component of flow from the Doppler velocities and wall motion velocities using the mass conservation equation. Although VFM provides 2-D flow, the algorithm is applicable only to bounded regions. Here, a modified VFM algorithm, vascular VFM, is proposed so that the velocities are estimated regardless of the flow geometry. To validate the algorithm, a phantom mimicking a carotid artery was fabricated and VFM velocities were compared with optical particle image velocimetry (PIV) data acquired in the same imaged plane. The validation results indicate that given optimal beam angle condition, VFM velocitiy is fairly accurate, where the correlation coefficient R between VFM and PIV velocities is 0.95. The standard deviation of the total VFM error, normalized by the maximum velocity, ranged from 8.1% to 16.3%, whereas the standard deviation of the measured input errors ranged from 8.9% to 12.7% for color flow mapping and from 4.5% to 5.9% for subbeam calculation. These results indicate that vascular VFM is reliable as its accuracy is comparable to that of conventional Doppler-flow images.
血管向量流图（VFM）方法通过使用质量守恒方程从多普勒速度和壁运动速度估计流的径向分量来可视化二维心脏流动力。尽管 VFM 提供了二维流，但该算法仅适用于有界区域。在此，提出了一种改进的 VFM 算法，即血管 VFM，以便无论流形如何都可以估计速度。为了验证该算法，制作了一个模拟颈动脉的体模，并将 VFM 速度与在相同成像平面中获得的光学粒子图像测速（PIV）数据进行了比较。验证结果表明，在最佳射束角度条件下，VFM 速度相当准确，其中 VFM 和 PIV 速度之间的相关系数 R 为 0.95。总 VFM 误差的标准偏差除以最大速度的范围为 8.1%至 16.3%，而彩色血流映射的测量输入误差的标准偏差范围为 8.9%至 12.7%，子束计算的标准偏差范围为 4.5%至 5.9%。这些结果表明，血管 VFM 是可靠的，因为其准确性可与传统的多普勒流图像相媲美。
