Schollenberger Jonas, Osborne Nicholas H, Hernandez-Garcia Luis, Figueroa C Alberto
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.
Department of Surgery, University of Michigan, Ann Arbor, MI, United States.
Front Bioeng Biotechnol. 2021 Aug 17;9:722445. doi: 10.3389/fbioe.2021.722445. eCollection 2021.
Cerebral hemodynamics in the presence of cerebrovascular occlusive disease (CVOD) are influenced by the anatomy of the intracranial arteries, the degree of stenosis, the patency of collateral pathways, and the condition of the cerebral microvasculature. Accurate characterization of cerebral hemodynamics is a challenging problem. In this work, we present a strategy to quantify cerebral hemodynamics using computational fluid dynamics (CFD) in combination with arterial spin labeling MRI (ASL). First, we calibrated patient-specific CFD outflow boundary conditions using ASL-derived flow splits in the Circle of Willis. Following, we validated the calibrated CFD model by evaluating the fractional blood supply from the main neck arteries to the vascular territories using Lagrangian particle tracking and comparing the results against vessel-selective ASL (VS-ASL). Finally, the feasibility and capability of our proposed method were demonstrated in two patients with CVOD and a healthy control subject. We showed that the calibrated CFD model accurately reproduced the fractional blood supply to the vascular territories, as obtained from VS-ASL. The two patients revealed significant differences in pressure drop over the stenosis, collateral flow, and resistance of the distal vasculature, despite similar degrees of clinical stenosis severity. Our results demonstrated the advantages of a patient-specific CFD analysis for assessing the hemodynamic impact of stenosis.
存在脑血管闭塞性疾病（CVOD）时的脑血流动力学受颅内动脉解剖结构、狭窄程度、侧支循环通路通畅情况以及脑微血管状况的影响。准确表征脑血流动力学是一个具有挑战性的问题。在这项工作中，我们提出了一种结合计算流体动力学（CFD）和动脉自旋标记磁共振成像（ASL）来量化脑血流动力学的策略。首先，我们利用ASL得出的 Willis 环血流分流情况来校准特定患者的CFD流出边界条件。随后，我们通过使用拉格朗日粒子追踪评估从主要颈部动脉到血管区域的分数血供，并将结果与血管选择性ASL（VS - ASL）进行比较，从而验证校准后的CFD模型。最后，在两名患有CVOD的患者和一名健康对照受试者中展示了我们所提出方法的可行性和能力。我们表明，校准后的CFD模型准确再现了从VS - ASL获得的血管区域分数血供。尽管两名患者的临床狭窄严重程度相似，但他们在狭窄处的压降、侧支血流以及远端血管阻力方面存在显著差异。我们的结果证明了针对特定患者的CFD分析在评估狭窄对血流动力学影响方面的优势。
