Data for: On the identification of hypoxic regions in subject-specific cerebral vasculature by combined CFD/MRI

A long-time exposure to lack of oxygen (hypoxia) in some regions of the cerebrovascular system is believed to be one of the causes of cerebral neurological disease. Performing {\em in vivo} studies on the human brain is complicated and can be highly risky for patients. In the present study, we show how a combination of Magnetic Resonance Imaging (MRI) and Computational Fluid Dynamics (CFD) can provide a non-invasive alternative for studying blood flow and transport of oxygen within the cerebral vasculature. We perform computer simulations of oxygen mass transfer in the subject-specific geometry of the Circle of Willis. The computational domain and boundary conditions are based on 4D flow MRI measurements. Two different oxygen mass transfer models are considered: passive (where oxygen is treated as a dilute chemical species in plasma) and active (where oxygen is bonded to hemoglobin) models. We show that neglecting hemoglobin transport results in a significant underestimation of the arterial wall-mass transfer of oxygen. We identified the hypoxic regions along the arterial walls by introducing the critical thresholds that are obtained by comparison of the estimated range of Damk\"{o}hler number ($Da\subset\langle9;57\rangle$) with the local Sherwood number. Finally, we recommend additional validations of the combined MRI/CFD approach proposed here for larger groups of subject- or patient-specific brain vasculature systems.

Methods
The results obtained are performed by the computational fluid dynamics (CFD) of the blood flow in the subject-specific of the brain vascular system. 

The data are saved in the Tecplot visualization software format (.plt).

脑血管系统局部区域长期处于缺氧（hypoxia）环境，被认为是诱发脑部神经系统疾病的重要诱因之一。对人类大脑开展体内（in vivo）研究不仅操作复杂，还会给患者带来极高风险。本研究证实，磁共振成像（Magnetic Resonance Imaging, MRI）与计算流体动力学（Computational Fluid Dynamics, CFD）的联合应用，可提供一种非侵入性方案，用于研究脑血管系统内的血液流动与氧气输运过程。我们针对威利斯环（Circle of Willis）的个体特异性几何结构，开展了氧气传质的计算机模拟。计算域与边界条件均基于4D流动磁共振成像（4D flow MRI）的测量数据。本研究采用两种不同的氧气传质模型：被动模型（将氧气视为血浆中的稀释化学物质）与主动模型（氧气与血红蛋白结合）。研究表明，忽略血红蛋白输运会显著低估动脉壁的氧气传质效率。我们通过将估算得到的达姆科勒数（Damköhler number, Da）范围（$Dasubsetlangle9;57
angle$）与局部舍伍德数（Sherwood number, Sh）进行对比，得到临界阈值，借此识别出动脉壁沿线的缺氧区域。最后，我们建议针对更大规模的个体或患者特异性脑血管系统群体，对本文提出的MRI/CFD联合方案开展进一步验证。
研究方法
本研究所得结果基于个体特异性脑血管系统内血液流动的计算流体动力学（CFD）模拟。
数据以Tecplot可视化软件格式（.plt）存储。