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1.
冠状动脉血管阻抗估计系统及其临床应用   总被引:1,自引:1,他引:1       下载免费PDF全文
利用PC机和图像、信号采集设备,建立冠状动脉血管阻抗的估计系统。该系统从血管内超声和血压检测仪器采集冠状动脉内的超声图像、血流多普勒和血压信号,通过提取管腔的截面积曲线和流速信息,获取血流量曲线。结合血压曲线,计算冠状动脉的等效阻抗。系统对不同程度冠脉狭窄、心肌架桥和微循环障碍病人进行临床应用,结果表明:血管阻抗可以反映血管供血和扩张能力与不同类型、程度病症间的关系,有望用于医学临床的辅助诊断。  相似文献   

2.
血栓多普勒信号的多参数提取及分类   总被引:1,自引:0,他引:1       下载免费PDF全文
血栓的准确检测可以用于早期脑血管疾病的诊断,超声多普勒是一种无损的血栓检测技术。文章使用三种信号处理方法:传统的声谱分析法、小波分析法、renyi信息量分析法对血栓多普勒信号进行分析,提取出相应的特征参数,然后对敏感的特征参数采用反向传输(Back-Propagation,简称BP)神经网络进行分类,建立起血栓、干扰噪声和正常血流信号的自动判别系统。通过对300例仿真多普勒信号和163例临床采集的大脑中动脉多普勒信号进行分析,结果表明:本文建立的系统对血栓的检测率高于传统的方法,有望可用于血栓多普勒信号的自动检测。  相似文献   

3.
超声多普勒系统中,脉冲多普勒采用分时设计将B模式成像和血流速度检测同时进行,导致了多普勒信号在成像阶段不可避免的缺失。为弥补由信号缺失所带来的信号不连续问题,降低对血流图像的干扰,一种基于自相关算法的多普勒信号预测方法在本文中被采用。  相似文献   

4.
利用超声多普勒技术检测血栓   总被引:6,自引:1,他引:5  
血栓检测对早期诊断血管疾病有十分重要的意义,超声多普勒技术是一种常用的血栓无损检测方法。当血栓通过超声多普勒仪器的采样容积时,会引起超声多普勒信号功率的瞬时增强,因此可以直接根据超声多普勒信号时域波形幅度的变化来检测血检。但是由于系统可能存在着干扰,这种基本的检测方法有着较大的局限。为了克服这一缺陷,可以利用信号处理的新理论,通过提取血栓信号的敏感特征参数,来达到提高血栓自动检测准确性的目的。  相似文献   

5.
方昕  汪源源  王威琪 《声学技术》2006,25(4):304-308
超声多普勒技术作为一种无损检测手段被广泛应用于血管狭窄的检测。以往的血管狭窄仿真信号的研究仅限于双边狭窄的对称情况,文章提出了一种单边狭窄血管中超声多普勒信号的仿真方法。首先用有限元分析方法(FEM)计算出狭窄血管中血流流速场分布情况,然后用总体分布非参数估计法计算出超声多普勒信号的功率谱密度(PSD),再用余弦叠加法获取仿真的超声多普勒时域信号。用快速傅里叶变换(FFT)计算仿真超声多普勒信号的频谱,从中计算最大频率、平均频率和频谱宽度等参数,分析它们在不同流速和狭窄程度下的特征,为血管疾病的诊断提供敏感的参数。  相似文献   

6.
刘炜 《影像技术》2013,(6):15-16
目的:探讨彩色多普勒超声对亚急性甲状腺炎(亚甲炎)的诊断价值。方法:;t~25N临床明确诊断的亚急性甲状腺炎患者进行彩色多普勒超声检查,并对结果进行回顾性分析。结果:亚急性甲状腺炎声像图特征:甲状腺实质内见片状均匀低回声区,形态不规则,边界模糊不清,病灶内少或无血流信号。结论:超声检查对亚急性甲状腺炎的诊断具有重要价值。  相似文献   

7.
目的:彩色多普勒超声检查可较敏感地反映移植肾血流动力学的改变,随时观察移植肾的成活情况,评价彩色多普勒超声在移植肾血管并发症中的应用效果。方法:回顾性分析9例移植肾血管并发症患者的彩色多普勒超声结果,观察肾结构、肾内血流信号的分布、肾静脉主干回声和血流充盈情况,测量主肾动脉、段动脉、叶间动脉及弓形动脉流速及阻力指数、搏动指数。结果:对2007年9月-2012年9月10例移植肾血管并发症进行分析,5例肾动脉狭窄,1例肾动脉栓塞,1例肾静脉狭窄,2例肾静脉血栓及1例假性动脉瘤。结论:彩色多普勒超声具有简便、迅速、无创、可重复性等优点,已成为肾移植后临床观察治疗效果的首选监测手段。它能客观、动态显示移植肾形态结构及其内部的血流分布,血流频谱形态、流速、舒张期血流方向和血流指数变化,及时发现移植肾血管并发症,查找导致移植肾功能损害的部分原因,早期明确诊断并给予及时治疗,对提高肾移植成功率起重要作用。  相似文献   

8.
正交相位法是超声多普勒技术中提取双向性血流信息的一种重要方法。由于正交信号对之间通常存在幅度和相位的不平衡,从而导致了正、反血流信息的混淆,影响了平均频率,最大的估计和声谱图的正确显示,本文提出的补偿方法,让其中一个正交信号通过按一定要求设计的线性滤波器,从而得到幅度和相位基本平衡的正交信号对,提高了超声多普勒系统提取双向性血流的性能。  相似文献   

9.
毛建丽 《影像技术》2013,25(2):8-8,10
目的:探讨彩色多普勒超声对剖宫产术后诊断子宫内膜异位至腹壁的超声表现及诊断价值。方法:对8例剖宫产术后腹壁切口处肿块来我院就诊并手术及病理诊断为腹壁子宫内膜异位症的二维及彩色多普勒超声特征。结果:8例患者包块均为剖宫产术后腹壁疤痕处内。其中4例位于腹壁皮下脂肪层内,2例位于脂肪层与腹直肌之间,2例位于腹直肌内,二维超声表现:呈不规则,无明显包膜,内部回声不均的低回声,包块后方回声稍衰减,CDFI显示肿块内部及周边可见点状或条状血流信号,为低速高阻的动脉血流。结论:彩色多普勒超声检查是子宫内膜异位至腹壁的有效辅助诊断方法.对可疑病例进行超声诊断具有较高的临床应用价值。  相似文献   

10.
多普勒血流信号最大频率曲线的特征分析及应用   总被引:2,自引:2,他引:0       下载免费PDF全文
文章主要研究从超声多普勒血流信号的最大频率曲线中提取特征值,并用于临床血管疾病诊断的方法。先利用短时傅里叶变换分析采样所得的音频多普勒血流信号,接着用百分比法得到信号的最大频率曲线,然后提取最大频率曲线频谱各峰值的比作为特征值,并将它们用于血管疾病的诊断。通过对颈动脉多普勒血流信号的临床分析表明:此方法比传统的声谱参数法有更高的诊断准确性。  相似文献   

11.
超声血流的无创伤检测和医学信号的特征提取   总被引:6,自引:0,他引:6  
人体信号是随机性和背景噪声都很强的复杂信号。文章首先研究了利用超声Doppler技术定量检测血流速度的方法,然后将一些现代信息处理中的新理论、新方法引入医学超声的信息处理,为医学超声信息的特征提取提供了新的手段。这些理论包括:分形、数学形态学、数量化、小波变换、极点轨迹和血管传输线模型等。文章最后阐述了利用上述新方法作为技术核心而研制的三套应用系统;肺动脉血液动力学参数的无损估测系统、彩色编码的声谱系统和超声血流定量检测系统。  相似文献   

12.
文章在笔记本计算机的硬件基础上建立了脐血流多普勒信号多参数分析的便携式系统。通过计算机声卡采集脐血流音频多普勒信号,然后进行传统的声谱参数分析、零极点模型分析、Teager算子分析和分形特征分析,应用Fisher多元判据法对四类特征参数进行分类决策,从而判断胎儿的生长情况。流速实验和临床试用的结果表明,该系统是有效的,可以应用于产科的临床诊断。  相似文献   

13.
Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s−1 with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation.  相似文献   

14.
Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications.  相似文献   

15.
Existing pulsed Doppler ultrasound systems apply the spectrogram as a tool for analysis and display of signals scattered from the blood. The spectrogram is a time-frequency representation (TFR) of a signal that maps a one-dimensional signal of time into a two-dimensional function of time and frequency. The analysis of Doppler ultrasound signals requires application of a two-dimensional TFR rather than one-dimensional spectral representations due to the nonstationary nature of the signals scattered from blood. The classical spectrogram is a smoothed Wigner distribution (SWD) with a specific smoothing function. For this smoothing function, the smoothing, and hence the resolution in time and frequency, cannot be controlled independently. The purpose of this study is to examine the application of other SWD's to analysis and display of Doppler ultrasound signals. The present paper concentrates on the pseudo-Wigner distribution (PWD). The PWD and the spectrogram are examined and compared as analysis tools for nonstationary Doppler ultrasound signals. The performance of these two TFR's as a function of Doppler bandwidth is evaluated and compared for time-varying flow  相似文献   

16.
Most of the important clinical indices of blood flow are estimated from the spectrograms of Doppler ultrasound (US) signals. Any noise may degrade the readability of the spectrogram and the precision of the clinical indiCes, so the spectral enhancement plays an important role in Doppler US signal processing. A new Doppler US spectral enhancement method is proposed in this paper and implemented in three main steps: the Gabor transform is used to compute the Gabor coefficients of a Doppler US signal, the spectral subtraction is performed on the magnitude of the Gabor coefficients, and the Gabor expansion with the spectral subtracted Gabor coefficients is used to reconstruct the denoised Doppler US signal. The different analysis and synthesis windows are examined in the Gabor transform and expansion. The signal-to-noise ratio (SNR) improvement together with the overall enhancement of spectrograms are examined on the simulated Doppler US signals from a femoral artery. The results show the denoising method based on the orthogonal-like Gabor expansion achieves the best denoising performance. The experiments on some clinical Doppler US signals from umbilical arteries confirm the superior denoising performance of the new method.  相似文献   

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