Auckland Bioengineering Institute, The University of Auckland, Auckland 1010, New Zealand.
IEEE Trans Biomed Eng. 2012 Mar;59(3):882-9. doi: 10.1109/TBME.2011.2181845. Epub 2011 Dec 26.
High-resolution (HR) electrical mapping is an important clinical research tool for understanding normal and abnormal gastric electrophysiology. Analyzing velocities of gastric electrical activity in a reliable and accurate manner can provide additional valuable information for quantitatively and qualitatively comparing features across and within subjects, particularly during gastric dysrhythmias. In this study, we compared three methods of estimating velocities from HR recordings to determine which method was the most reliable for use with gastric HR electrical mapping. The three methods were 1) simple finite difference (FD) 2) smoothed finite difference (FDSM), and 3) a polynomial-based method. With synthetic data, the accuracy of the simple FD method resulted in velocity errors almost twice that of the FDSM and the polynomial-based method, in the presence of activation time error up to 0.5 s. With three synthetic cases under various noise types and levels, the FDSM resulted in average speed error of 3.2% and an average angle error of 2.0° and the polynomial-based method had an average speed error of 3.3% and an average angle error of 1.7°. With experimental gastric slow wave recordings performed in pigs, the three methods estimated similar velocities (6.3-7.3 mm/s), but the FDSM method had a lower standard deviation in its velocity estimate than the simple FD and the polynomial-based method, leading it to be the method of choice for velocity estimation in gastric slow wave propagation. An improved method for visualizing velocity fields is also presented.
高分辨率（HR）电描记法是理解正常和异常胃电生理学的重要临床研究工具。以可靠和准确的方式分析胃电活动速度可以提供更多有价值的信息，用于定量和定性地比较跨个体和个体内的特征，特别是在胃节律紊乱期间。在这项研究中，我们比较了三种从 HR 记录中估计速度的方法，以确定哪种方法最可靠，可用于胃 HR 电描记。这三种方法是 1）简单有限差分（FD）2）平滑有限差分（FDSM）和 3）基于多项式的方法。使用合成数据，在激活时间误差高达 0.5 秒的情况下，简单 FD 方法的准确性导致速度误差几乎是 FDSM 和基于多项式的方法的两倍。在各种噪声类型和水平下的三个合成案例中，FDSM 导致平均速度误差为 3.2%，平均角度误差为 2.0°，基于多项式的方法的平均速度误差为 3.3%，平均角度误差为 1.7°。在用猪进行的实验性胃慢波记录中，三种方法估计的速度相似（6.3-7.3mm/s），但 FDSM 方法的速度估计标准差低于简单 FD 和基于多项式的方法，使其成为胃慢波传播中速度估计的首选方法。还提出了一种改进的可视化速度场的方法。
