Moen Christian Arvei, Salminen Pirjo-Riitta, Dahle Geir Olav, Hjertaas Johannes Just, Grong Ketil, Matre Knut
Department of Clinical Science, University of Bergen, Haukeland University Hospital, Bergen NO-5021, Norway.
Cardiovasc Ultrasound. 2013 Aug 22;11:32. doi: 10.1186/1476-7120-11-32.
Speckle Tracking Echocardiography (STE) strain analysis relies on both spatial and temporal smoothing. The user is often allowed to adjust these smoothing parameters during analysis. This experimental study investigates how different degrees of user controllable spatial and temporal smoothing affect global and regional STE strain values in recordings obtained from normal and ischemic myocardium.
In seven anesthetized pigs, left ventricular short- and long-axis B-mode cineloops were recorded before and after left anterior descending coronary artery occlusion. Peak- and postsystolic global STE strain in the radial, circumferential and longitudinal direction as well as corresponding regional strain in the anterior and posterior walls were measured. During post-processing, strain values were obtained with three different degrees of both spatial and temporal smoothing (minimum, factory default and maximum), resulting in nine different combinations.
All parameters for global and regional longitudinal strain were unaffected by adjustments of spatial and temporal smoothing in both normal and ischemic myocardium. Radial and circumferential strain depended on smoothing to a variable extent, radial strain being most affected. However, in both directions the different combinations of smoothing did only result in relatively small changes in the strain values. Overall, the maximal strain difference was found in normal myocardium for peak systolic radial strain of the posterior wall where strain was 22.0 ± 2.2% with minimal spatial and maximal temporal smoothing and 30.9 ± 2.6% with maximal spatial and minimal temporal smoothing (P < 0.05).
Longitudinal strain was unaffected by different degrees of user controlled smoothing. Radial and circumferential strain depended on the degree of smoothing. However, in most cases these changes were small and would not lead to altered conclusions in a clinical setting. Furthermore, smoothing did not affect strain variance. For all strain parameters, variance remained within the corresponding interobserver variance.
斑点追踪超声心动图（STE）应变分析依赖于空间和时间平滑处理。在分析过程中，用户通常可以调整这些平滑参数。本实验研究旨在探讨不同程度的用户可控空间和时间平滑处理如何影响从正常和缺血心肌记录中获得的整体和局部STE应变值。
对7只麻醉猪在左前降支冠状动脉闭塞前后记录左心室短轴和长轴B模式电影环。测量径向、圆周和纵向方向的收缩期峰值和收缩后整体STE应变以及前壁和后壁相应的局部应变。在后期处理过程中，采用三种不同程度的空间和时间平滑处理（最小、出厂默认和最大）获得应变值，从而产生九种不同组合。
正常和缺血心肌中，整体和局部纵向应变的所有参数均不受空间和时间平滑处理调整的影响。径向和圆周应变在不同程度上依赖于平滑处理，径向应变受影响最大。然而，在两个方向上，不同的平滑处理组合仅导致应变值相对较小的变化。总体而言，在正常心肌中，后壁收缩期峰值径向应变的最大应变差异被发现，其中最小空间和最大时间平滑处理时应变为22.0±2.2%，最大空间和最小时间平滑处理时应变为30.9±2.6%（P＜0.05）。
纵向应变不受用户控制的不同程度平滑处理的影响。径向和圆周应变依赖于平滑程度。然而，在大多数情况下，这些变化很小，不会在临床环境中导致结论改变。此外，平滑处理不影响应变方差。对于所有应变参数，方差仍在相应的观察者间方差范围内。
