Puiseux Thomas, Sewonu Anou, Moreno Ramiro, Mendez Simon, Nicoud Franck
IMAG, University Montpellier, CNRS, Montpellier, France.
Spin Up, Strasbourg, France.
PLoS One. 2021 Mar 26;16(3):e0248816. doi: 10.1371/journal.pone.0248816. eCollection 2021.
A numerical approach is presented to efficiently simulate time-resolved 3D phase-contrast Magnetic resonance Imaging (or 4D Flow MRI) acquisitions under realistic flow conditions. The Navier-Stokes and Bloch equations are simultaneously solved with an Eulerian-Lagrangian formalism. A semi-analytic solution for the Bloch equations as well as a periodic particle seeding strategy are developed to reduce the computational cost. The velocity reconstruction pipeline is first validated by considering a Poiseuille flow configuration. The 4D Flow MRI simulation procedure is then applied to the flow within an in vitro flow phantom typical of the cardiovascular system. The simulated MR velocity images compare favorably to both the flow computed by solving the Navier-Stokes equations and experimental 4D Flow MRI measurements. A practical application is finally presented in which the MRI simulation framework is used to identify the origins of the MRI measurement errors.
本文提出了一种数值方法，用于在实际流动条件下高效模拟时间分辨三维相位对比磁共振成像（或四维流动磁共振成像）采集。采用欧拉-拉格朗日形式同时求解纳维-斯托克斯方程和布洛赫方程。为降低计算成本，开发了布洛赫方程的半解析解以及周期性粒子播种策略。首先通过考虑泊肃叶流动配置验证了速度重建流程。然后将四维流动磁共振成像模拟程序应用于心血管系统典型的体外流动模型内的流动。模拟的磁共振速度图像与通过求解纳维-斯托克斯方程计算的流动以及实验性四维流动磁共振成像测量结果相比都具有优势。最后给出了一个实际应用，其中磁共振成像模拟框架用于识别磁共振成像测量误差的来源。
