心音信号奇异点的小波分析方法

本文利用小波变换方法,提出以确定奇异点的位置以及幅值的变化对心音信号进行参数估计.通过PhysioBank数据库中的相关数据,运用Madab对正常心音和病理性心音信号进行小波变换分析,对奇异点做了检测.并与傅里叶变换结果作对比分析.通过对变换后的心音信号进行分析,研究结果表明:利用小波变换技术分析与处理心音信号是一种新的有效和实用的方法.可以为心音信号的分析或医学诊断提供有价值的信息.     

心音信号噪声消除的小波变换方法

心音信号幅值小,干扰多,采用常规的时、频域滤波方法往往不能收到良好的效果,本文根据信号和干扰在小波变换下的不同变化特性,利用二进小波变换的模极大值识别出心音信号中的干扰噪声的位置,剔除其相应的小波变换系数后,再通过小波逆变换重构出心音信号,并根据心音信号的特点选取了适当的母小波和分解尺度,给出了利用小波方法去噪前后的实际结果,结果表明,小波变换方法可有效地消除心音信号中的噪声干扰。     

基于盒维数的心音信号分形特征研究

在传统盒维数的基础上,从尺度变化的角度,提出一种计算心音信号时域波形分形维数的新的二进盒维数算法,并给出了算法思想和估算方法;然后用该方法对正常心音和几种典型的病态心音的分形维数进行计算,并对其分形特征进行了研究．研究结果表明：心音信号具有明显的分形特征,分形维数能够反映心音信号的复杂程度,并且能够明显地区分正常心音和病态心音．     

心音信号的分析方法及其应用

心音信号包含了关于人体丰富的病理信息,其分析与研究为心血管疾病的诊断提供了很重要的临床依据.本文探讨了心音信号分析的研究现状,及其短时傅立叶变换(STFT),小波变换(WT),Hilbert-Huang变换在心音信号分析中的应用以及需要解决的理论问题,并运用PhysioBank数据库中的ECG数据,将Hilbert变换运用于ECG信号的分析中,结合MATLAB软件,做出了较为理想的瞬时频率图.     

超声心动图检测胎儿心包积液的临床价值

目的:探讨超声心动图检测胎儿心包积液的临床意义。方法:2007-2010年在我院检查行超声心动图检查的高危孕妇473例,同时设对照组,检测孕龄在20-40周无明显高危妊娠因素的孕妇472例,并将产前超声检查结果和胎儿尸检或分娩后超声心动图检查结果进行对照。结果:1.高危组检出72例心包积液,检出率12.5%,对照组检出13例心包积液,检出率3%,两组胎儿心包积液检出率间差别有统计学意义(x2=39.57,P<0.05)。2.85例心包积液中,孤立性心包积液38例,伴其他心脏畸形或者其他系统畸形47例,其中孤立性心包积液预后良好。结论:超声心动图能够敏感地检出胎儿心包积液;心包积液程度并不是最重要的,其伴随心脏畸形或者其他畸形决定预后。     

超声心动图检测胎儿心包积液的临床价值

目的：探讨超声心动图检测胎儿心包积液的临床意义。方法：2007-2010年在我院检查行超声心动图检查的高危孕妇473例,同时设对照组,检测孕龄在20-40周无明显高危妊娠因素的孕妇472例,并将产前超声检查结果和胎儿尸检或分娩后超声心动图检查结果进行对照。结果：1.高危组检出72例心包积液,检出率12.5%,对照组检出13例心包积液,检出率3%,两组胎儿心包积液检出率间差别有统计学意义（x2=39.57,P〈0.05）。2.85例心包积液中,孤立性心包积液38例,伴其他心脏畸形或者其他系统畸形47例,其中孤立性心包积液预后良好。结论：超声心动图能够敏感地检出胎儿心包积液;心包积液程度并不是最重要的,其伴随心脏畸形或者其他畸形决定预后。     

脉冲超声多普勒胎心率检测与处理

胎儿心率的检测是胎儿监护的最主要的项目之一。胎心率的变化趋势与胎儿的健全程度(Well-being)、供氧状况、胎儿活力状况密切相关。围产期,特别是妊娠末期和分娩过程中,对胎心率进行监测,可及时发现胎儿在宫内缺氧、窘迫等危重症状,以便采取相应对策,保障新生儿的健康。胎心信号的获取是准确地测定胎心率的前提。胎心信号的获取方法主要有微音器法(FPCG)、胎儿心电法(FECG)和超声多普勒法。微音器法获取的是胎儿心音信号,它易受内外环境声音的干扰。胎儿心电法获取的是胎儿心电信号,可用直接法取得或经母体     

应激条件下人群心脏储备动用趋势的特征研究

目的:探讨应激条件下人群心脏储备动用趋势的复杂度特征。方法:应用运动心力监测仪采集运动员(A组,n=15)和普通大学生(B组,n=15)静息和不同负荷运动后即刻的心音信号,分析心动周期里心音信号的样本熵。结果:静息状态、1 750J、3 500 J、5 250 J、7 000 J 4种不同负荷后即刻运动员和普通大学生的心动周期心音样本熵值均呈下降趋势,且运动员样本熵值均低于普通大学生的。静息时两人群样本熵值未显统计学差异,而运动负荷后即刻表现出显著性差异(P0.05)。静息状态、1 750J、3 500 J、5 250 J、7 000 J 4种不同负荷后即刻运动员心率均低于普通大学生心率,而且普通大学生和运动员的心音样本熵与心率和运动负荷均呈显著(P0.05)相关关系,相关系数分别为-0.671和-0.745。结论:样本熵可以作为评估应激条件下人群心脏储备动用趋势的指标,且能区分普通大学生与运动员的心脏储备动用趋势差异。     

提高光声成像质量的Renyi熵方法

针对光声成像数据采集系统中获得的超声数据存在杂波问题,提出一种先基于Renyi熵分离超声信号和杂波,再利用分离后的超声数据进行光声成像的方法。光声成像平台实验表明,通过Renyi熵的直方图来选择超声信号和杂波分离的阈值,可以有效地滤除超声信号中的大部分杂波。成像重构的评估结果也验证了该结论。可见,该文提出的方法能有效滤除超声采集数据中的杂波,从而提高光声成像的质量。     

基于血流多普勒原理的血压测量系统设计

血流信号的采集可基于超声多普勒技术。利用多普勒超声探头在肢体主动脉脉搏处采集到血流多普勒频移信号,对信号电压进行放大,一方面直接输入扬声器转变为音频信号,得到多普勒音;同时用频率/电压变换器LM331变换多普勒频移信号,得到脉搏波信号。基于此原理,设计了使用无创、直观的方法获得肢体血流参数,并经PC机处理,最终在显示器上显示脉搏波形和血压数值的方法。     

多切面法联合彩色多普勒超声在胎儿先天性心脏病诊断中的应用

目的:探讨多切面法联合彩色多普勒超声在胎儿先天性心脏病(congenital heart diseases,CHD)诊断中的应用价值。方法:采用多切面法联合彩色多普勒超声对2015年5月~2016年7月300例胎儿进行CHD筛查,并与随访的产后超声或尸解结果作对照。结果:300例胎儿经产前超声联合多切面法检出CHD胎儿20例,检出率为6.7%,经产后超声或尸解确诊14例:三尖瓣下移畸形1例,室间隔完整型完全性大动脉转位1例,完全性房室间隔缺损1例,室间隔完整型肺动脉瓣闭锁1例,双流入型单心室1例,共同动脉干Ⅰ型2例,单纯室间隔缺损2例,法洛氏四联症2例,主动脉弓缩窄1例,肺动脉瓣轻度狭窄1例,二尖瓣闭锁并共同动脉干1例;误诊为单纯室间隔缺损1例,误诊为法洛氏四联症1例,病例流失4例。产前超声联合多切面法对有、无高危因素的检出率分别为3.79%、13.48%,比较有统计学意义(P0.05)。产前超声联合多切面法诊断CHD的灵敏度为100%、特异度为99.66%、阳性预测值为80.00%、阴性预测值为100%。结论:多切面法联合彩色多普勒超声在胎儿CHD诊断中具有较高的应用价值。     

Continuous Fetal Heart Rate Monitoring and Tocodynamometry in Routine Obstetrical Care,Fetal Stress and Non-Stress Testing,and Labor Induction in the Chimpanzee (Pan troglodytes)

The use of continuous fetal heart rate (FHR) and uterine pressure monitoring in the chimpanzee (Pan troglodytes) by external Doppler transducer and tocodynamometer is described in 1) the routine obstetrical assessment of fetal well-being, 2) oxytocin challenge (stress) testing (OCT) and non-stress testing (NST) for the diagnosis of in utero fetal distress, and 3) induction of labor by intravenous oxytocin infusion, by surgical rupture of the chorio-amniotic membranes (amniotomy), or by a combination of these techniques, as an alternative to Caesarean section for clinical, managemental, or experimental purposes. FHR traces were analyzed during a total of 57 term pregnancies for three basic characteristics: baseline rate, variability, and periodic pattern. Results indicated that continuous FHR monitoring in the chimpanzee can provide a valuable tool for fetal assessment and management of labor in any attempt to reduce the unacceptably high annual incidence of perinatal and neonatal infant mortality reported in the U.S.     

Isolation of Fetal ECG Signals from Abdominal ECG Using Wavelet Analysis

ObjectiveMonitoring the heartbeat of the fetus during pregnancy is a vital part in determining their health. Current fetal heart monitoring techniques lack the accuracy in fetal heart rate monitoring and features acquisition, resulting in diagnostic medical issues. The demand for a reliable method of non-invasive fetal heart monitoring is of high importance.MethodElectrocardiogram (ECG) is a method of monitoring the electrical activity produced by the heart. The extraction of the fetal ECG (FECG) from the abdominal ECG (AECG) is challenging since both ECGs of the mother and the baby share similar frequency components, adding to the fact that the signals are corrupted by white noise. This paper presents a method of FECG extraction by eliminating all other signals using AECG. The algorithm is based on attenuating the maternal ECG (MECG) by filtering and wavelet analysis to find the locations of the FECG, and thus isolating them based on their locations. Two signals of AECG collected at different locations on the abdomens are used. The ECG data used contains MECG of a power of five to ten times that of the FECG.ResultsThe FECG signals were successfully isolated from the AECG using the proposed method through which the QRS complex of the heartbeat was conserved, and heart rate was calculated. The fetal heart rate was 135 bpm and the instantaneous heart rate was 131.58 bpm. The heart rate of the mother was at 90 bpm with an instantaneous heart rate of 81.9 bpm.ConclusionThe proposed method is promising for FECG extraction since it relies on filtering and wavelet analysis of two abdominal signals for the algorithm. The method implemented is easily adjusted based on the power levels of signals, giving it great ease of adaptation to changing signals in different biosignals applications.     

四维彩超技术在筛查胎儿先天性心脏病的应用价值分析

目的:探讨四维彩超技术在筛查胎儿先天性心脏病的应用价值。方法:择取我院2012年3月至2014年3月收治的行产前筛查的300例产妇为研究对象,采用四维彩色多普勒超声择取心脏三血管、四腔观、肺动脉分叉、上下腔静脉回流、动脉导管弓、主动脉弓等常规切面,予以胎心各腔血流及胎心率等多项检测,对胎儿是否存在先心病进行综合诊断,并综合胎儿大体解剖状况,与病理诊断及二维超声检查结果进行对比。结果:四维彩超检出率为6.67%,正确率为90.00%;二维超声检出率为6.00%,正确率为83.33%,两组比较差异具有统计学意义(P0.05)。结论:四维彩超技术在筛查胎儿先天性心脏病中具有至关重要的应用价值,有助于指导胎儿先天性心脏病早期治疗,保证患儿预后,值得临床借鉴。     

高危孕妇胎儿缺氧与彩色多普勒超声结合四维超声检查的相关性研究

摘要 目的：探讨与研究高危孕妇胎儿缺氧与彩色多普勒超声结合四维超声检查的相关性。方法：2018年2月到2020年1月在本院进行建档分娩的高危孕妇108例作为研究对象,都给予彩色多普勒超声结合四维超声检查,记录影像学特征,判定胎儿缺氧发生情况并进行相关性分析。结果：在高危孕妇108例中,发生宫内缺氧28例（宫内缺氧组）,发生率为25.9 %;宫内缺氧组的大脑中动脉、脐动脉的阻力指数（RI）、搏动指数（PI）、收缩期峰值流速舒张期流速比值（S/D）均高于非宫内缺氧组（P<0.05）;宫内缺氧组的上腔静脉血流心室收缩期峰值流速（S波）、心房收缩期速度（A波）、心室舒张期峰值流速（D波）均高于非宫内缺氧组（P<0.05）;高危孕妇108例中,Spearsman分析显示大脑中动脉、脐动脉的RI、PI、S/D以及上腔静脉血流S、D、A均与宫内缺氧都存在相关性（P<0.05）;logistic多因素回归分析显示：大脑中动脉、脐动脉的S/D与上腔静脉血流S、A为导致胎儿缺氧的主要影响因素（P<0.05）。结论：高危孕妇胎儿缺氧与彩色多普勒超声结合四维超声检查特征具有相关性,彩色多普勒超声结合四维超声可作为检查胎儿缺氧的可行、简单无创、方便快捷的方式,具有极高的应用价值。     

产前超声在中孕期胎儿严重先天性心脏病筛查中的应用

目的:探究产前超声检查在中孕期胎儿严重先天性心脏病(CHD)筛查中的应用。方法:选择2012年1月至2014年1月在我院妇产科进行产前常规超声检查的孕妇12076例,年龄22-41岁,平均(28.6±8.3)岁,孕周20-36周,平均(25.2±6.7)周。将符合纳入排除标准的孕妇8953例作为研究对象,其中初产妇6023例,经产妇2930例。对纳入研究的孕妇行彩色多普勒超声检查,并对妊娠结局进行追踪,将确诊情况与筛查结果进行比较分析。结果:产前彩色多普勒超声诊断出胎儿CHD38例,经尸检或新生儿彩色多普勒超声检查均确诊为CHD,对胎儿期未筛查出CHD的孕妇进行新生儿彩色多普勒超声检查,确诊4例,产前超声检查胎儿CHD检出率为90.48%(38/42),检出准确率100%(38/38)。结论:彩色多普勒超声筛查孕中期胎儿CHD,灵敏度和特异性高,安全无创伤,操作简便快速,值得推广为产前筛查的首选方法。     

Study of the development of uteroplacental and fetal feline circulation by triplex Doppler

The objective was to evaluate blood flow in fetal and maternal vessels by Triplex Doppler and its association with development of blood vessels during gestation in the domestic cat. Ten queens were examined weekly from 14 to 63 d after mating. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI) of uteroplacental, aorta and umbilical fetal arteries and caudal vena cava of the fetus were evaluated. Throughout pregnancy, there was an increase in PSV and EDV in the aorta and umbilical arteries. In the caudal vena cava, there was an increase in PSV, whereas the EDV was constant, with a significant increase on Day 63. Peak systolic velocity and EDV of the uteroplacental artery reduced significantly on Day 63. Resistance index of the umbilical artery progressively decreased. In the aorta, this reduction was detected only on Day 42, with no defined pattern in the caudal vena cava and uteroplacental artery. Pulsatility index of the aorta varied. Although pulsatility increased in the caudal vena cava on Day 35 and remained elevated, pulsatility was significantly reduced in the umbilical artery by Day 63. The pulsatility index of the uteroplacental artery was constant (increased only on Day 63). Triplex Doppler evaluation could be a useful adjunct for prenatal care of pregnant queens, including assessment of vascular gestational development and prediction of gestational age.     

The fetal circadian rhythm in pregnancies complicated by pregestational diabetes is altered by maternal glycemic control and the morning cortisol concentration

Circadian rhythmicity is fundamental to human physiology, and is present even during fetal life in normal pregnancies. The impact of maternal endocrine disease on the fetal circadian rhythm is not well understood. The present study aimed to determine the fetal circadian rhythm in pregnancies complicated by pregestational diabetes mellitus (PGDM), compare it with a low-risk reference population, and identify the effects of maternal glycemic control and morning cortisol concentrations. Long-term fetal electrocardiogram recordings were made in 40 women with PGDM at 28 and 36 weeks of gestation. Two recordings were made in 18 of the women (45.0%) and one recording was made in 22 (55.0%). The mean fetal heart rate (fHR) and the fHR variation (root mean square of squared differences) were extracted in 1-min epochs, and circadian rhythmicity was detected by cosinor analysis. The study cohort was divided based on HbA1c levels and morning cortisol concentrations. Statistically, significant circadian rhythms in the fHR and the fHR variation were found in 45 (100%) and 44 (95.7%) of the 45 acceptable PGDM recordings, respectively. The rhythms were similar to those of the reference population. However, there was no statistically significant population-mean rhythm in the fHR among PGDM pregnancies at 36 weeks, indicating an increased interindividual variation. The group with higher HbA1c levels (>6.0%) had no significant population-mean fHR rhythm at 28 or 36 weeks, and no significant fHR-variation rhythm at 36 weeks. Similarly, the group with a lower morning cortisol concentration (≤8.8 µg/dl) had no significant population-mean fHR-variation rhythm at 28 and 36 weeks. These findings indicate that individual fetal rhythmicity is present in pregnancies complicated by PGDM. However, suboptimal maternal glycemic control and a lower maternal morning cortisol concentration are associated with a less-well-synchronized circadian system of the fetus.