三维人胸主动脉中血流动力学的数值研究

目的分离与重建人体胸主动脉弓的三维仿真模型,对人体胸主动脉中的脉冲血流进行三维数值模拟和研究。方法运用计算流体力学的基本原理和血流动力学的相关知识,依据临床上采集到的人胸CT扫描数据,运用图像处理软件Mimics分离并重建人体胸主动脉弓的三维仿真模型。结果计算出当以抛物型脉冲血流作为初始速度时,正常人的胸主动脉内血液流动在心动周期内不同时刻的血液流场、壁面压力、速度分布。主动脉弓与分支血管交界面远心端的血流速度明显高于近心端的血流速度,主动脉弓段内外壁血流存在明显的压力差,血流速度和压力变化剧烈区域,特别是左锁骨下动脉分出点以下约2～3cm处的局部区域,与临床主动脉夹层易发区域相吻合。这说明血流压力和速度对胸主动脉夹层的发生有很大的影响。结论基于CT扫描数据进行数值模拟与仿真建模有利于深入开展生物流体力学研究,而主动脉弓血液流场的数值模拟对临床主动脉夹层的诊断和治疗提供了很大的帮助。

comThree-dimensional simulation of blood flow in human thoracic aorta

Objective To reconstruct a three-dimensional model of the human thoracic aorta, so as to numerically simulate and study the pulsating blood flow in human thoracic aorta. Methods A three-dimensional reconstruction of the human thoracic aorta arch was obtained using CT scan imaging on a human aorta by Mimics, a software for image processing. The numerical simulations were obtained based on the principle of computational fluid mechanics and hemodynamics. Results The distribution of velocity, pressure, and path of the blood flow in the aortic arch of normal people were calculated at a given pulsating and parabolic initial cycle. Our numerical results demonstrated that the blood velocity of distal end was greatly faster than that of proximal end on the interface between branch and aortic arch. There was an obvious pressure gradient between the inner wall and outer wall of blood vessels. The areas where the blood velocity and pressure changed greatly were consistent with the location of the thoracic aortic dissection, especially the area 2-3 cm below the left subclavian artery, suggesting that the blood pressure and velocity may greatly influence the progress of aortic dissection. Conclusion Numerical simulation and modeling based on CT scan data can help to study bio-fluid mechanics. At the same time, the numerical simulation of blood flow will greatly help the diagnosis and treatment of the aortic dissection and arteriosclerosis.