技术论文和演示文稿

简介：测量心脏血流的当前金标准是心脏磁共振（CMR）和Color-Doppler Ultrasound [Ref1]。提出的模拟管道从医学成像中提取心脏壁运动，并模拟心脏内血流，作为直接测量的替代方法。该管道旨在通过两种方式与这些直接测量方法竞争：1：更好的时空分辨率2：较短的获取时间（呼吸较少，平均心跳平均）

该管道应用于动态心脏幻影以进行验证。材料：动态心脏幻影是雪莱医学成像技术（加拿大多伦多）的双腹膜。幻影安装在底座上，可以使用附着在幻影顶点处的杆上的伺服电动机来操纵（压缩和扭转，请参见图1）。将流体从储层中泵送到右侧心室的入口，其流量恒定，而心脏幻像以每分钟75次（bpm）的速度压缩10毫米。方法：使用计算机断层扫描（CTA）扫描动态心脏幻像，该扫描术（CTA）提供了解剖学的时间依赖性3D图像。时间分辨率为每个心脏周期20卷。对于75 bpm的心率，产生的样品周期为0.8s/20 = 0.04。空间分辨率为0.6x0.6x0.5（mm）^3.流体结构域是从单个时间实例中分割的，并在comsolMultiphysics®中导入为表面网格。188金宝搏优惠移动是从所有时间实例的体积图像登记中获得的位移场的规定，即从CTA获得的所有3D帧。因此，位移场具有与CTA相同的时间分辨率。 The segmentation and volumetric image registration is performed in MATLAB. COMSOL Multiphysics®: The heavy computational lifting is performed in COMSOL Multiphysics®. Here the surface mesh is imported and inlet, outlet and wall boundaries are defined. Moving mesh is defined for entire region and “prescribed mesh displacement” is applied to the “wall” boundary. This approach is first tested using an analytic function corresponding to the known phantom movement and later defined from the displacement field obtained from volumetric image registration. The displacement field is discrete in time and space and necessitates 4D interpolation which is implemented as an external MATLAB function. Like the phantom setup the inlet flow rate is constant 5 L/min and the outlet pressure is constant (arbitrarily set to 0 Pa). The wall has zero slip conditions where u⃗fluid=u⃗wall at the wall boundary. Results: It was possible to recreate the right phantom ventricle geometry and movement for geometry prescribed CFD in COMSOL Multiphysics®. This setup allows direct comparison with other imaging modalities such as ultrasound. The flow patterns obtained from the CFD is qualitatively similar to direct measurements using ultrasound vector flow imaging.

参考文献1：心脏内流可视化：当前状态和未来方向D.Muños等。al。（2013）https://doi.org/10.1093/ehjci/jet086 Ref2：开发卡内血液中的计算流体动力学的验证平台R. Hvid等。al。（2019）https://doi.org/10.1109/ultsym.2019.8925893