Shields A, Setlur Nagesh S V, Chivukula V, Ionita C, Bednarek D R, Rudin S
Canon Stroke and Vascular Research Center, University at Buffalo, Buffalo, NY.
Department of Biomedical Engineering, Florida Institute of Technology, Melbourne, FL.
Proc SPIE Int Soc Opt Eng. 2022 Feb-Mar;12036. doi: 10.1117/12.2611175. Epub 2022 Apr 4.
Pathological changes in blood flow lead to altered hemodynamic forces, which are responsible for a number of conditions related to the remodeling and regeneration of the vasculature. More specifically, wall shear stress (WSS) has been shown to be a significant hemodynamic parameter with respect to aneurysm growth and rupture, as well as plaque activation leading to increased risk of stroke. In-vivo measurement of shear stress is difficult due to the stringent requirements on spatial resolution near the wall boundaries, as well as the deviation from the commonly assumed parabolic flow behavior at the wall. In this work, we propose an experimental method of in-vitro WSS calculations from high-temporal resolution velocity distributions, which are derived from 1000 fps high-speed angiography (HSA). The high-spatial and temporal resolution of our HSA detector makes such high-resolution velocity gradient measurements feasible. Presented here is the methodology for calculation of WSS in the imaging plane, as well as initial results for a variety of vascular geometries at physiologically realistic flow rates. Further, the effect of spatial resolution on the gradient calculation is explored using CFD-derived velocity data. Such angiographic-based analysis with HSA has the potential to provide critical hemodynamic feedback in an interventional setting, with the overarching objective of supporting clinical decision-making and improving patient outcomes.
血流的病理变化会导致血流动力学力的改变，而这些力与许多与血管重塑和再生相关的病症有关。更具体地说，壁面切应力（WSS）已被证明是与动脉瘤生长和破裂以及导致中风风险增加的斑块激活相关的一个重要血流动力学参数。由于对壁边界附近的空间分辨率有严格要求，以及与壁面处通常假设的抛物线形流动行为存在偏差，因此在体内测量切应力很困难。在这项工作中，我们提出了一种从高时间分辨率速度分布进行体外WSS计算的实验方法，该速度分布由1000帧每秒的高速血管造影（HSA）得出。我们的HSA探测器的高空间和时间分辨率使得这种高分辨率速度梯度测量成为可能。这里展示的是成像平面中WSS的计算方法，以及在生理现实流速下各种血管几何形状的初步结果。此外，使用CFD得出的速度数据探索了空间分辨率对梯度计算的影响。这种基于HSA血管造影的分析有可能在介入环境中提供关键的血流动力学反馈，其总体目标是支持临床决策并改善患者预后。
