应用实体动态模型对三维磁性传感取样法的研究

A study of three-dimensional magnetic sensor acquisition: using a dynamic in vitro model

目的:评价三维磁性传感系统测量左心室每搏容积的准确性。材料与方法:将模拟左心室的乳胶气球模型悬浮在水槽中,与能产生10个不同每搏输出量的泵相连(20～65mlbeat)。用三维Echopac软件根据Simpson’法测量气球的容s积,分别与传统的二维面积长度法(0.5AL)所测容积及直接测量气球容积所得的参考值比较。结果:三维法测值(=0.91x+Y0.41r=0.97SEE=2.83ml,P<0.001,,)比二维法测值(Y=0.49x+8.68r=0.87SEE=3.87ml,P<0.001,,)具有更好的相关性;三维与二维法之间差异具有非常显著性意义,P<0.001。结论:三维磁性传感取样法实用准确,有利于对左心室功能的评价。

Objective: To evaluate the accuracy of this three-dimensional(3D) magnetic position sensor system in the quantification of ventricular stroke volumes in a dynamic model. Methods: A latex balloon model of the left ventricle was suspended in a water bath connected to a pump producing 10 different pulsatile stroke volumes(20～65ml/beat). Scanning was performed using a 5.0MHz transducer mounted with a magnetic receiver(GE System Five). The probe was scanned to sweep continuously across and over the balloon volume over 3～7s. Digital loops were stored on magneto-optical disk and reviewed retrospectively using 3D Echopac software(GE) based on Simpson's method and compared with a two-dimensional(2D) biplane area-length method(0.5AL) measurements at end systole and end diastole. Both 3D and 2D derived stroke volumes were compared with the reference stroke volume calculated by direct measurement of balloon capacity. Results: There was an improved correlation between 3D stroke volume and reference stroke volume(Y=0.91x+0.41, r=0.97, SEE=2.83ml, P<0.001) compared to 2D stroke volume and reference stroke volume(Y=0.49x+8.68, r=0.87, SEE=3.87ml, P<0.001), there is significant difference between 2D and 3D(P<0.001). Conclusion: 3D magnetic scanning is practical, accurate and should facilitate assessment of left ventricular function.