图像数值分析在人工机械心脏瓣膜运动特征中的应用

Numerical Images Analysis Applied for Artificial Mechanical Heart Valve Movement Characteristic

动态图像测量技术是一种非接触式、动态、精确的检测运动物体特性的分析方式。人工心脏瓣膜体外动态开闭性能测试,依靠高速图像摄影技术捕捉瓣膜的细微运动,快速图像和精准的时间记录,将瓣膜运动转化为图像信息,分析瓣膜及各组件运动时的相对位移和速度变化,有效地解析瓣膜运动状况,为评价瓣膜性能提供参考。在人工心脏瓣膜脉动流平台上,选择双叶型机械心脏瓣膜在正常心动条件下,采用高速摄影技术通过标记点跟踪瓣膜瓣叶运动,记录瓣膜的运动轨迹及运动状态;通过图像数值分析瓣膜开启和关闭的运动情况,将瓣膜运动过程离散为多步静止状态的图像,离散后的图像数据导入Matlab数值分析,解析瓣膜中瓣叶的转动速度及角加速度等运动状态。以此改善瓣膜结构与流场之间的相互作用,改进瓣膜使用性能,结合瓣膜临床病症特征,解决瓣膜类相关并发症。

Dynamic image measure technology is an advanced analyzed method which can detect the movement of substance indirectly, dynamically as well accurately. Generally, to measure the in-vitro opening and closing performances of artificial heart valves the sophisticate movements of valves are firstly captured by using high speed imaging photography. Then these recorded instantaneous pictures and associated time information are translated into specifical image information. After professionally digital analysis, relative displacement and speed changes among each valvular component can be achieved. In this way, the valve moving performances can be represented efficiently, meanwhile providing valuable evaluating information for the artificial heart valves. The bileaflet mechanical heart valves as experimental objects which move under the conditions of pulsating flow was chosed. The high speed imaging technology was applied to investigate the kinestate and moving trails of valves by recording the traces of mark points on the valvular leaflets. Then the digital image analysis was used to analyze those marker traces and determine the opening or closing motion states of valves. During digital analysis, all high speed image information from the valve motions firstly needs to be dispersed into multistep images of static state which, after numerical analysis of Matlab, can finally propose specifically leaflet kinestate of valves, such as rotational velocity and angular acceleration. Our research sheds some lights of the interactions between valve structure and flow flied and guides directions on perfecting valve performances with the hope of solving related complications of mechanical artificial heart valves in clinical.