Department of Civil and Environmental Engineering, North Dakota State University, CIE 201, 1410 North 14th Avenue, Fargo, ND 58105-5285, United States; NDSU-UND Biomedical Engineering Program, United States; Center for Cellular Biointerfaces in Science and Engineering, United States.
J Biomech. 2021 Feb 12;116:110238. doi: 10.1016/j.jbiomech.2021.110238. Epub 2021 Jan 13.
The transition of the inflow jet to turbulence is crucial in understanding the pathology of brain aneurysms. Previous works Le et al. (2010, 2013) have shown evidence for a highly dynamic inflow jet in the ostium of brain aneurysms. While it is highly desired to investigate this inflow jet dynamics in clinical practice, the constraints on spatial and temporal resolutions of in vivo data do not allow a detailed analysis of this transition. In this work, Dynamic Mode Decomposition (DMD) is used to identify the most energetic modes of the inflow jet in patient-specific models of internal carotid aneurysms via the utilization of high-resolution simulation data. It is hypothesized that dynamic modes are not solely controlled by the blood flow waveform at the parent artery. They are also dependent on jet-wall interaction phenomena. DMD analysis shows that the spatial extent of low- frequency modes corresponds well to the most energetic areas of the inflow jet. The high-frequency modes are short-lived and correspond to the flow separation at the proximal neck and the jet's impingement onto the aneurysmal wall. Low-frequency modes can be reconstructed at relatively low spatial and temporal resolutions comparable to ones of in vivo data. The current results suggest that DMD can be practically useful in analyzing blood flow patterns of brain aneurysms with in vivo data.
流入射流向湍流的转变对于理解脑动脉瘤的病理学至关重要。Le 等人之前的工作（2010 年，2013 年）已经证明了脑动脉瘤入口处存在高度动态的流入射流。虽然非常希望在临床实践中研究这种流入射流动力学，但体内数据的空间和时间分辨率的限制不允许对这种转变进行详细分析。在这项工作中，通过利用高分辨率模拟数据，对颈内动脉动脉瘤的患者特定模型中的流入射流进行动态模式分解（DMD），以识别最具活力的模式。假设动态模式不仅受母动脉血流波形的控制。它们还取决于射流壁相互作用现象。DMD 分析表明，低频模式的空间范围与流入射流的最具活力区域非常吻合。高频模式的寿命较短，对应于近端颈部的流动分离和射流对动脉瘤壁的冲击。低频模式可以在相对较低的空间和时间分辨率下进行重建，与体内数据的分辨率相当。目前的结果表明，DMD 可以在分析脑动脉瘤的血流模式方面具有实际的应用价值。
