经胸三维超声心动图评价左室收缩功能方法的初步研究

目的　探讨采用磁场定位系统经胸三维超声心动图(3DE)测定左室收缩功能的方法及可行性。方法　健康志愿者17例。利用磁场发射及接收装置通过手动控制探头在心尖区扇形扫描进行三维数据采集。每例受检者均分别采集60、30及10幅图像（3D60、3D30、3D10）各自进行三维重建。同时记录采集时间。采用圆盘总和法（disksummation）测定左室舒张末期容积（LVEDV）和左室收缩末期容积（LVESV），得出每搏输出量（SV）及左室射血分数（LVEF）。同时用常规二维Simpson法测量LVEF。结果　①3D10重建后的左室短轴图像不完整，左室壁有不规则中断，心腔内结构难以评价。3D60及3D30重建后的左室短轴图像完整，内膜、二尖瓣及瓣下结构清晰可辨。②二维超声心动图(2DE)测得LVEF为0.62±0.06，与3D60及3D30的测值显著相关（r值分别为0.87，0.83，P<0.001）。③3D60测定的EDV，ESV，SV及EF分别为（88.11±18.08）ml、（38.01±9.23）ml、（50.09±13.30）ml和0.57±0.07；3D30测定的EDV，ESV，SV及EF分别为（87.51±15.58）ml、（37.18±9.62）ml、（50.33±11.48）ml和0.58±0.08；二者间各项测值差异无显著性意义（P均>0.1），且显著相关（r值分别为0.94，0.88，0.88，0.87，P均<0.001）。④3D60的采集时间为（152.55±53.27）s，3D30的采集时间为（72.82±17.16）s，比3D60的时间节省48％。结论　磁场定位系统扇形扫描经胸3DE测定正常人左室收缩功能是准确可行的。采集30幅图像与采集60幅图像得到的左室收缩功能指标无显著差异，前者可缩短约一半的检查时间，更加迅速方便，有利于临床应用。

Assessment of left ventricular function by transthoracic three dimensional echocardiography

Objective　To investigate the feasibility and best method in the assessment of left ventricular (LV) function with transthoracic three-dimensional echocardiography(3DE).Methods　Transthoracic 3DE LV data sets were acquired in 17 normal subjects using 60, 30 and 10 slices （3D60、3D30、3D10）respectively with a magnetic tracking system and freehand device. The LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) were measured from each 3DE data set with the “summation of disks” method, and stroke volume (SV) and ejection fraction (LVEF) was derived from those. LVEF from 2DE using Simpson method was also measured.Results　① The reconstruction image of 3D10 was incomplete with many irregular interruptions in the LV wall. The images of 3D60 and 3D30 were clear, and cardiac structures could be well defined. ② LVEF from 2DE was 0.62±0.06, which showed excellent correlation with LVEF from 3D60 and 3D30 (r=0.87 and 0.83, respectively, P<0.001). ③ No significant differences (P>0.1, respectively), but excellent correlation in EDV，ESV，SV and EF were found between 3D60 and 3D30. ④ The 3D30 acquisition time was (72.82±17.16)s, which was 48% less than the 3D60 acquisition time (152.55±53.27)s.Conclusions　It is feasible to assess LV function by transthoracic 3DE with a magnetic tracking system and freehand device. Since 3D30 has the same accurate results as 3D60 and can save half of the acquisition time. It is more suitable for clinical use.