Division of Biological Engineering, Monash University, Victoria, 3800, Australia.
Ann Biomed Eng. 2011 Jun;39(6):1643-53. doi: 10.1007/s10439-011-0260-2. Epub 2011 Feb 4.
High resolution in vivo velocity measurements within the cardiovascular system are essential for accurate calculation of vessel wall shear stress, a highly influential factor for the progression of arterial disease. Unfortunately, currently available techniques for in vivo imaging are unable to provide the temporal resolution required for velocity measurement at physiological flow rates. Advances in technology and improvements in imaging systems are allowing a relatively new technique, X-ray velocimetry, to become a viable tool for such measurements. This study investigates the haemodynamics of pulsatile blood flow in an optically opaque in vitro model at physiological flow rates using X-ray velocimetry. The in vitro model, an asymmetric stenosis, is designed as a 3:1 femoral artery with the diameter and flow rate replicating vasculature of a mouse. Velocity measurements are obtained over multiple cycles of the periodic flow at high temporal and spatial resolution (1 ms and 29 μm, respectively) allowing accurate measurement of the velocity gradients and calculation of the wall shear stress. This study clearly illustrates the capability of in vitro X-ray velocimetry, suggesting it as a possible measurement technique for future in vivo vascular wall shear stress measurement.
在心血管系统中进行高分辨率的体内速度测量对于准确计算血管壁切应力至关重要，而血管壁切应力是动脉疾病进展的一个极其重要的影响因素。不幸的是，目前用于体内成像的技术无法提供在生理流速下进行速度测量所需的时间分辨率。技术的进步和成像系统的改进使得一种相对较新的技术，即 X 射线速度测量技术，成为此类测量的一种可行工具。本研究使用 X 射线速度测量技术在生理流速下对光学不透明的体外模型中的脉动血流进行血流动力学研究。体外模型为不对称狭窄，设计为具有 3:1 股动脉直径和流量的模型，其直径和流量复制了小鼠的脉管系统。速度测量是在周期性流动的多个周期内获得的，具有高时间和空间分辨率（分别为 1 ms 和 29 μm），从而可以准确测量速度梯度并计算壁面切应力。本研究清楚地说明了体外 X 射线速度测量的能力，表明其可能成为未来体内血管壁切应力测量的一种测量技术。
