摘要
Objective To evaluate the accuracy of a 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 (15-65mi/beat). Scanning was performed using a 5.0 mHz transducer mounted with a Flock of Birds (FOB) magnetic receiver (GE System Five). The probe was scanned to sweep continuously across and over the balloon volume over 3 - 7 seconds. Digital loops were stored on magneto-optical disks and reviewed retrospectively using 3D Echopac software (GE)based on Simpson's method and compared with a two-dimensional (2D) biplane area-length method (1/2L x R) 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 = 0.91 x + 0.41, r = 0.97, SEE = 2.83 ml, P = 0.0001 ) compared to 2D stroke volume and reference stroke volume (y=0.49x+8.68, r=0.87, SEE=3.87 ml, P=0.0011, difference between 2D and 3D P＜0.003).Conclusion 3D magnetic FOB scanning is practical, accurate and should facilitate assessment of left ventricular function.
目的 三维鸟瞰磁性取样法在患者有限的胸前声窗取样中具有潜在的快速及灵活的优越性 ,本研究的设计用来评价三维磁性传感系统在动态实体模型下对左心室每搏容积定量测量的准确性。方法 将一个代表左心室的乳胶气球膜型悬浮在水槽中 ,并与能产生 1 0个不同每搏输出量的泵相连1 5-6 5ｍｌ/ｂｅａｔ) ,探头频率 5 0ＭＨｚ,并装有鸟瞰 (ＦＯＢ)磁性接收器 (ＧＥ系统五 ) ,探头连续移动扫描气球 3 -7秒。所有图象贮存在磁盘上 ,用三维Ｅｃｈｏｐａｃ软件 (ＧＥ)根据Ｓｉｍｐｓｏｎ’ｓ法测量气球的容积 ,并与分别在收缩末期和舒张末期用传统的二维法 (1 / 2面积乘长度 )所测得的容积比较。最后将三维和二维法所测得的每搏输出量与直接测量气球容积所得的参考每搏输出量比较。结果 相比较二维法所测得的每搏输出量与参考值之间的相关性 (ｙ =0 .49ｘ +8.6 8,ｒ=0 .87,ＳＥＥ =3 .87ｍｌ,Ｐ=0 .0 0 1 1 ;ｄｉｆｆｅｒｅｎｃｅｂｅｔｗｅｅｎ 2Ｄａｎｄ 3Ｄ ,Ｐ <0 .0 0 3 ) ,三维法所测值与参考值之间具有更好的相关性 (ｙ =0 .91ｘ +0 .41 ,ｒ=0 .97,ＳＥＥ =2 .83ｍｌ,Ｐ =0 .0 0 0 1 )。结论 三维鸟瞰磁性取样法实用准确 。
