【摘要】 目的:激光多普勒血流仪测得的皮肤平均血流灌注量和血流速度等这些传统的评估微循环的参数指标在电磁场对人体微循环影响的研究中并没有得到跟其在动物实验中相似的结果。因而本研究欲利用时频分析技术寻求新的评估人体微循环的参数指标,给人体激光多普勒血流灌注信号的分析和处理提供新的思路和方法,为后续电磁场对人体微循环影响的研究奠定基础。方法:运用在低频段具有较高频率分辨率的连续小波变换将二维激光多普勒血流灌注信号转换为包含时间和频率信息的三维信号,由此可以清楚地同时观察小波变换后的小波系数在不同频段随着时间的变化情况。结果:小波变换后的小波系数在0.005 Hz~2 Hz频率范围内存在6个可能与微循环控制机理有关的特征峰值,峰值的幅度随着时间有所变化。结论:小波变换可作为分析人体激光多普勒血流灌注信号的一种有效工具,为后续电磁场对人体微循环影响的研究奠定基础,并且其对微弱、背景噪声强的医学信号的分析和处理提供了新的思路和方法。更多还原

【Abstract】 Objective: The traditional physiological parameters such as mean values of skin blood flux(SBF) and velocity of skin blood flow measured by laser Doppler flowmetry(LDF) in the study of effects of electromagnetic fields to human microcirculation were not in line with the result in animal experiments.This study aimed to find new parameters evaluating human microcirculation by using time-frequency analysis which may provide a new idea and method for analysis and processing human SBF signal and lay a foundation for future study of effects of electromagnetic fields to human microcirculation.Methods: Continuous wavelet transform which has superior frequency resolution in low frequency band was applied to convert two dimensional data of perfusion signal into three dimensional involving the temporal and frequency information of the original signal,thus we can investigate how wavelet coefficients in different frequency bands vary with time.Results: Six characteristic peaks identified relating to microvascular mechanism can be recognized in the frequency interval between 0.005 Hz and 2 Hz and the amplitude of each peak change with time.Conclusions: Wavelet transform can be used as an effective tool to analyze human SBF signal and provides a new idea and method for analyzing and processing of medical signal which are usually weak and involved strong background noise.更多还原