Validation of CFD simulations of cerebral aneurysms with implication of geometric variations
Validation of CFD simulations of cerebral aneurysms with implication of geometric variations
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DOI：
10.1115/1.2354209
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发表时间：
2006-12-01
影响因子：
1.7
通讯作者：
Meng, Hui
中科院分区：
文献类型：
--
作者：
Hoi, Yiemeng;Woodward, Scott H.;Meng, Hui
背景使用基于医学图像的解剖血管几何结构的计算流体动力学（CFD）模拟现在正获得临床相关性。本研究旨在通过粒子图像测速（PIV）测量验证用于研究脑动脉瘤的CFD方法，重点关注动脉瘤模型中的小几何变化对CFD获得的流动动力学的影响。接近的方法。实验体模由硅橡胶制成，以最佳模拟球形动脉瘤模型。从体模获得PIV测量结果，并与理想球形动脉瘤模型（S1）的CFD结果进行比较。这些测量结果也进行了比较，计算流体动力学的结果，根据实验体模的三维图像重建的几何形状。我们进一步对体模的两个几何变化S2和S3进行了CFD分析，以研究小的几何变化对微流场的影响。结果我们发现理想球形动脉瘤模型的CFD结果与体模的PIV测量结果之间的一致性较差，包括不一致的二次流模式。然而，基于实际体模几何结构的CFD结果与PIV测量结果匹配良好。模型S2和S3的计算流体动力学（CFD）产生了与体模类似的定性流场，但在关键血流动力学参数（如涡度、正循环和壁面剪切应力）方面发生了定量显著变化。结论只要在相同的模型几何形状上进行计算流体力学模拟，计算流体力学模拟结果就可以与实验测量结果非常接近。动脉瘤模型上的微小几何变化可显著改变流场和关键血流动力学参数。由于医学图像受到几何不确定性的影响，因此在提供临床反馈之前，必须仔细检查基于图像的患者特定CFD结果。
Background. Computational fluid dynamics (CFD) simulations using medical-image-based anatomical vascular geometry are now gaining clinical relevance. This study aimed at validating the CFD methodology for studying cerebral aneurysms by using particle image velocimetry (PIV) measurements, with a focus on the effects of small geometric variations in aneurysm models on the flow dynamics obtained with CFD. Method of Approach. An experimental phantom was fabricated out of silicone elastomer to best mimic a spherical aneurysm model. PIV measurements were obtained from the phantom and compared with the CFD results from an ideal spherical aneurysm model (S1). These measurements were also compared with CFD results, based on the geometry reconstructed from three-dimensional images of the experimental phantom. We further performed CFD analysis on two geometric variations, S2 and S3, of the phantom to investigate the effects of small geometric variations on the aneurysmal flow field. Results. We found poor agreement between the CFD results from the ideal spherical aneurysm model and the PIV measurements from the phantom, including inconsistent secondary flow patterns. The CFD results based on the actual phantom geometry, however, matched well with the PIV measurements. CFD of models S2 and S3 produced qualitatively similar flow fields to that of the phantom but quantitatively significant changes in key hemodynamic parameters such as vorticity, positive circulation, and wall shear stress. Conclusion. CFD simulation results can closely match experimental measurements as long as both are performed on the same model geometry. Small geometric variations on the aneurysm model can significantly alter the flow field and key hemodynamic parameters. Since medical images are subjected to geometric uncertainties, image-based patient-specific CFD results must be carefully scrutinized before providing clinical feedback.