CREATIS UMR 5220, U1294, University Lyon 1, INSA Lyon, France.
IMAG UMR 5149, University of Montpellier, France.
Phys Med Biol. 2022 Apr 19;67(9). doi: 10.1088/1361-6560/ac62fe.
. Intraventricular vector flow mapping (VFM) is a velocimetric technique for retrieving two-dimensional velocity vector fields of blood flow in the left ventricular cavity. This method is based on conventional color Doppler imaging, which makesVFM compatible with the clinical setting. We have generalized theVFM for a three-dimensional reconstruction (3D-VFM).3D-VFM is able to recover three-component velocity vector fields in a full intraventricular volume by using a clinical echocardiographic triplane mode. The 3D-VFM problem was written in the spherical (radial, polar, azimuthal) coordinate system associated to the six half-planes produced by the triplane mode. As with the 2D version, the method is based on the mass conservation, and free-slip boundary conditions on the endocardial wall. These mechanical constraints were imposed in a least-squares minimization problem that was solved through the method of Lagrange multipliers. We validated 3D-VFMin a patient-specific CFD (computational fluid dynamics) model of cardiac flow and tested its clinical feasibilityin patients and in one volunteer.The radial and polar components of the velocity were recovered satisfactorily in the CFD setup (correlation coefficients,r = 0.99 and 0.78). The azimuthal components were estimated with larger errors (r = 0.57) as only six samples were available in this direction. In bothandinvestigations, the dynamics of the intraventricular vortex that forms during diastole was deciphered by 3D-VFM. In particular, the CFD results showed that the mean vorticity can be estimated accurately by 3D-VFM.. Our results tend to indicate that 3D-VFM could provide full-volume echocardiographic information on left intraventricular hemodynamics from the clinical modality of triplane color Doppler.
. 心室内向量血流图（VFM）是一种血流速度测量技术，用于获取左心室腔内二维血流速度矢量场。该方法基于传统彩色多普勒成像，使 VFM 与临床环境兼容。我们已经将 VFM 推广到三维重建（3D-VFM）。3D-VFM 通过使用临床超声心动图三平面模式，能够在整个心室内体积内恢复三维速度矢量场。3D-VFM 问题是在与三平面模式产生的六个半平面相关的球形（径向、极、方位）坐标系中编写的。与 2D 版本一样，该方法基于质量守恒和心内膜壁的自由滑移边界条件。这些力学约束被施加在最小二乘最小化问题中，该问题通过拉格朗日乘子法求解。我们在心脏流动的特定于患者的 CFD（计算流体动力学）模型中验证了 3D-VFM，并在患者和一名志愿者中测试了其临床可行性。速度的径向和极向分量在 CFD 设置中得到了令人满意的恢复（相关系数，r=0.99 和 0.78）。方位分量的估计误差较大（r=0.57），因为在该方向上只有六个样本可用。在和两项研究中，3D-VFM 揭示了舒张期间形成的左室内涡流的动力学。特别是，CFD 结果表明，3D-VFM 可以准确估计平均涡度。我们的结果表明，3D-VFM 可以从三平面彩色多普勒的临床模式为左心室室内血流动力学提供全容积超声心动图信息。
