Characteristics of Wall Shear Stress and Pressure of Intracranial Atherosclerosis Analyzed by a Computational Fluid Dynamics Model: A Pilot Study

Zimo Chen; Haiqiang Qin; Jia Liu; Bokai Wu; Zaiheng Cheng; Yong Jiang; Liping Liu; Lina Jing; Xinyi Leng; Jing Jing; Yilong Wang; Yongjun Wang

doi:10.3389/fneur.2019.01372

Characteristics of Wall Shear Stress and Pressure of Intracranial Atherosclerosis Analyzed by a Computational Fluid Dynamics Model: A Pilot Study

Front Neurol. 2020 Jan 17:10:1372. doi: 10.3389/fneur.2019.01372. eCollection 2019.

Authors

Zimo Chen^{1

2}, Haiqiang Qin^{1

2

3

4}, Jia Liu⁵, Bokai Wu⁵, Zaiheng Cheng⁵, Yong Jiang^{1

2

3

4}, Liping Liu^{1

2

3

4}, Lina Jing⁶, Xinyi Leng⁷, Jing Jing^{1

2

3

4}, Yilong Wang^{1

2

3

4}, Yongjun Wang^{1

2

3

4}

Affiliations

¹ Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
² China National Clinical Research Center for Neurological Diseases, Beijing, China.
³ Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China.
⁴ Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China.
⁵ Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
⁶ Department of Radiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
⁷ Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, China.

Abstract

Background: 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. Materials and Methods: 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. Results: Among the 55 atherosclerotic lesions analyzed by this TOF-MRA based computational fluid dynamics model, the maximum WSS (WSS_max) 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_max and pressure drop increased with significantly increasing steep beyond 50% stenosis. Moreover, WSS_max was found to linearly correlate with pressure drop in ICAS. Conclusions: 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.

Keywords: cerebral hemodynamics; intracranial atherosclerosis; magnetic resonance angiography; mathematical modeling; pressure; wall shear stress.