Nagaoka Ryo, Hasegawa Hideyuki
Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan.
J Med Ultrason (2001). 2020 Apr;47(2):167-177. doi: 10.1007/s10396-019-00998-4. Epub 2020 Jan 2.
In high-resolution wavenumber analysis for detection of pulse wave velocity (PWV), phase information of analytic signals is used to estimate the wavenumber. However, the phase information could be affected by the adjacent signals in the temporal direction. Therefore, we propose a modified high-resolution wavenumber analysis technique using real acceleration waveforms of the arterial wall.
In the modified wavenumber analysis, we propose a new evaluation function that corresponds to the inverse of the squared coefficient of variation. The accuracy of estimation of PWV was investigated by performing simulations, and the feasibility was also examined in an in vivo experiment.
In the simulation experiments, the estimation accuracy using the proposed method was comparable to that using the previous method using phase information. However, when the pulse wave included the reflection components, the PWV estimated using the proposed method was more stable than that estimated using the previous method. Also, in the in vivo experiments, at opening of the aortic valve, the velocity estimated by the proposed method was almost equal to that estimated by the previous method (previous: 2.97 ± 1.2 m/s, proposed: 4.82 ± 1.4 m/s). Meanwhile, when the reflection components were present, the estimated PWV values yielded by the previous and proposed methods were - 1.13 and - 3.50 ± 0.9 m/s, respectively. The PWVs at those two time points estimated by the previous method were quite different, and the PWV estimate was considered to be more affected by the reflected waves.
The results of the simulations and in vivo experiments indicated that the modified high-resolution wavenumber analysis method was less affected by the reflected waves and more accurate in estimation of PWVs of both the forward and reflected waves.
在用于检测脉搏波速度（PWV）的高分辨率波数分析中，解析信号的相位信息被用于估计波数。然而，相位信息可能会受到时间方向上相邻信号的影响。因此，我们提出一种使用动脉壁实际加速度波形的改进型高分辨率波数分析技术。
在改进的波数分析中，我们提出一种新的评估函数，它对应于变异系数平方的倒数。通过进行模拟研究了PWV估计的准确性，并在体内实验中检验了其可行性。
在模拟实验中，使用所提出方法的估计精度与使用先前基于相位信息的方法相当。然而，当脉搏波包含反射成分时，使用所提出方法估计的PWV比使用先前方法估计的更稳定。此外，在体内实验中，在主动脉瓣开放时，所提出方法估计的速度与先前方法估计的速度几乎相等（先前方法：2.97±1.2米/秒，所提出方法：4.82±1.4米/秒）。同时，当存在反射成分时，先前方法和所提出方法得到的估计PWV值分别为-1.13和-3.50±0.9米/秒。先前方法在这两个时间点估计的PWV差异很大，并且认为PWV估计受反射波的影响更大。
模拟和体内实验结果表明，改进的高分辨率波数分析方法受反射波的影响较小，并且在估计正向波和反射波的PWV方面更准确。
