Grabskaya Eva, Spira Corinna, Hoffmann Renate, Altiok Ertunc, Ocklenburg Christina, Hoffmann Rainer, Becker Michael
Medical Clinic I, University Hospital RWTH Aachen, Germany.
Echocardiography. 2010 Aug;27(7):809-14. doi: 10.1111/j.1540-8175.2010.01158.x.
Doppler derived strain analysis has been shown to be angle dependent. Speckle tracking analysis using 2D echocardiographic images is thought to provide angle independent parameters of regional and global myocardial function. This study sought to evaluate whether myocardial circumferential strain and rotation derived from automatic frame-by-frame tracking of natural acoustic markers is dependent on angulation of the transducer.
In 48 healthy volunteers (mean age 36 ± 3 years, 20 male) parasternal short-axis views at apical level were obtained as follows: at the standard parasternal position (5th intercostal space) with a most possible circular short-axis image of the left ventricle (angulation 1), at an angulation of the transducer by 20° from this standard position to the apex (angulation 2) and at an angulation of the transducer by 20° to the base of the left ventricle (angulation 3). Using an automatic frame-by-frame tracking system of natural acoustic echocardiographic markers (EchoPAC, GE Ultrasound, Horton, Norway) circumferential strain and rotation were calculated for six segments within a short-axis circumference.
Image quality was sufficient for acquisition and analysis of images at all three-transducer angulation in 90% of the analyzed segments. Rotation was measured to be 7.7 ± 1.2° at angulation 1, 2.7 ± 0.9° at angulation 2 and 4.3 ± 1.1° at angulation 3 (p < 0.05). Average circumferential strain data was found to be -27.2 ± 5.1% at angulation 1, -26.5 ± 3.8% at angulation 2 and 28.9 ± 4.4% at angulation 3 (p = 0.287).
Circumferential strain analysis is not dependent on transducer angulation. In contrast, determination of myocardial rotation is dependent on transducer angulation. Therefore, accurate transducer angulation has to be taken care of if rotation measurements are performed.
已证明多普勒衍生应变分析存在角度依赖性。使用二维超声心动图图像的斑点追踪分析被认为可提供区域和整体心肌功能的角度独立参数。本研究旨在评估从自然声学标记的自动逐帧追踪得出的心肌圆周应变和旋转是否依赖于换能器的角度。
对48名健康志愿者（平均年龄36±3岁，20名男性）获取心尖水平的胸骨旁短轴视图如下：在标准胸骨旁位置（第5肋间）获取最可能为圆形的左心室短轴图像（角度1），换能器从该标准位置向心尖成20°角（角度2），以及换能器向左心室底部成20°角（角度3）。使用自然声学超声心动图标记的自动逐帧追踪系统（EchoPAC，通用电气超声，挪威霍顿）计算短轴圆周内六个节段的圆周应变和旋转。
在90%的分析节段中，图像质量足以在所有三个换能器角度采集和分析图像。角度1时旋转测量值为7.7±°，角度2时为2.7±0.9°，角度3时为4.3±1.1°（p<0.05）。平均圆周应变数据在角度1时为-27.2±5.1%，角度2时为-26.5±3.8%，角度3时为28.9±4.4%（p = 0.287）。
圆周应变分析不依赖于换能器角度。相比之下，心肌旋转的测定依赖于换能器角度。因此，如果进行旋转测量，必须注意准确的换能器角度。
