Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
Department of aeronautics and astronautics, Fudan University, Shanghai, China.
Comput Methods Biomech Biomed Engin. 2021 Nov;24(15):1718-1729. doi: 10.1080/10255842.2021.1912742. Epub 2021 Sep 26.
The flow velocity of visceral arteries was measured by 2D PCMRI to produce the patient-specific flow BC imposed on the outlets of visceral arteries in CFD simulation. This modified method aimed to improve the CFD accuracy in the abdominal aorta and visceral arteries.
A volunteer underwent non-contrast-enhanced MRA to scan the abdominal aorta and visceral arteries, and 2D PCMRI to obtain the flow velocity of the aforementioned vessels. The three-dimensional geometric model was reconstructed using the MRI scan data of the abdominal aorta and visceral arteries. The flow waveforms measured by 2D PCMRI were processed and then imposed on the aortic inlet and the outlets of all visceral arteries as the flow BC. The RCR parameters of the three elements Windkessel model were modulated and imposed on the aortic outlet. CFD simulation was run in the open-source software: svSolver. The same volunteer underwent 4D flow MRI to compare the flow field with those extracted from CFD results.
Four specific time points in a cardiac cycle and three cross-sectional planes of aorta were selected to analyze the flow field, pressure and wall shear stress (WSS) from CFD. The flow waveforms and streamlines of CFD agreed with those of 4D flow MRI. The pressure waveforms, pressure distribution and WSS distribution from CFD conformed with the physiological condition of human body.
These results suggest this modified CFD method may yield reasonable flow field, pressure and WSS in the abdominal aorta and visceral arteries.
通过二维 PCMRI 测量内脏动脉的血流速度，为 CFD 模拟中内脏动脉出口处施加患者特定的血流边界条件。这种改进的方法旨在提高腹主动脉和内脏动脉中 CFD 的准确性。
一名志愿者接受非对比增强 MRA 扫描腹主动脉和内脏动脉，并进行二维 PCMRI 以获得上述血管的血流速度。使用 MRI 扫描数据重建腹主动脉和内脏动脉的三维几何模型。通过二维 PCMRI 测量的血流波形进行处理，然后作为血流边界条件施加到主动脉入口和所有内脏动脉的出口。Windkessel 模型的三个元素的 RCR 参数进行调制，并施加到主动脉出口。CFD 模拟在开源软件 svSolver 中运行。同一名志愿者接受 4D 流 MRI 检查，以比较与从 CFD 结果中提取的流场。
从 CFD 中分析了心脏周期的四个特定时间点和主动脉的三个横截面平面的流场、压力和壁面切应力（WSS）。CFD 的血流波形和流线与 4D 流 MRI 的一致。CFD 的压力波形、压力分布和 WSS 分布符合人体的生理状况。
这些结果表明，这种改进的 CFD 方法可能会在腹主动脉和内脏动脉中产生合理的流场、压力和 WSS。
