Chen Zimo, Qin Haiqiang, Liu Jia, Wu Bokai, Cheng Zaiheng, Jiang Yong, Liu Liping, Jing Lina, Leng Xinyi, Jing Jing, Wang Yilong, Wang Yongjun
Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
China National Clinical Research Center for Neurological Diseases, Beijing, China.
Front Neurol. 2020 Jan 17;10:1372. doi: 10.3389/fneur.2019.01372. eCollection 2019.
Although wall shear stress (WSS) and pressure play important roles in plaque vulnerability, characteristics of the two indices in intracranial atherosclerosis (ICAS) have not been fully investigated yet. This study aimed to elucidate this issue by means of establishing a non-invasive computational fluid dynamics method with time-of-flight magnetic resonance angiography (TOF-MRA) of the whole cerebral artery. Subjects with symptomatic ICAS in the middle cerebral artery domain were enrolled, excluding those with concomitant internal carotid artery stenosis. Based on patient-specific TOF-MRA images for three-dimensional (3D) meshes and arterial blood pressure with patient-specific carotid artery ultrasonography for inlet boundary conditions, patients' three-dimensional hemodynamics were modeled by a finite element method governed by Navier-Stokes equations. Among the 55 atherosclerotic lesions analyzed by this TOF-MRA based computational fluid dynamics model, the maximum WSS (WSS) was most frequently detected at the apex points and the upper half of the upstream sections of the lesions, whereas the maximum pressure was most often located at the lower half of the upstream sections. As the percent stenosis increases, the relative value of WSS and pressure drop increased with significantly increasing steep beyond 50% stenosis. Moreover, WSS was found to linearly correlate with pressure drop in ICAS. This study on ICAS revealed certain trends of longitudinal distribution of WSS and pressure and the influences of percent stenosis on cerebral hemodynamics, as well as the correlations between WSS and pressure drop. It represents a step forward in applying computational flow simulation techniques in studying ICAS and stroke, in a patient-specific manner.
尽管壁面剪应力（WSS）和压力在斑块易损性中起着重要作用，但这两个指标在颅内动脉粥样硬化（ICAS）中的特征尚未得到充分研究。本研究旨在通过建立一种基于全脑动脉飞行时间磁共振血管造影（TOF-MRA）的非侵入性计算流体动力学方法来阐明这一问题。纳入大脑中动脉区域有症状的ICAS患者，排除伴有颈内动脉狭窄的患者。基于针对三维（3D）网格的患者特异性TOF-MRA图像以及针对入口边界条件的患者特异性颈动脉超声检查获得的动脉血压，采用由纳维-斯托克斯方程控制的有限元方法对患者的三维血流动力学进行建模。在通过基于TOF-MRA的计算流体动力学模型分析的55个动脉粥样硬化病变中，最大WSS最常出现在病变顶点和病变上游部分的上半部分，而最大压力最常位于上游部分的下半部分。随着狭窄百分比增加，WSS和压力降的相对值增加，在狭窄超过50%时显著增加且斜率明显增大。此外，发现ICAS中WSS与压力降呈线性相关。这项关于ICAS的研究揭示了WSS和压力的纵向分布趋势、狭窄百分比对脑血流动力学的影响以及WSS与压力降之间的相关性。它代表了以患者特异性方式将计算流体模拟技术应用于研究ICAS和中风方面向前迈进的一步。
