应用音频处理系统无创自动估测肺动脉压的研究

目的：探索音频处理系统无创自动估测肺动脉压的价值。方法：对５１例左向右分流的先心病患儿,应用多普勒超声技术和音频处理系统,根据改良肺动脉／主动脉血流时间间期比法同步估测肺动脉收缩压、平均压,并与心导管实测值对比。结果：音频处理系统估测肺动脉压所需时间短于多普勒超声技术所需时间（Ｐ＜０．０１）,且重复性较好。音频处理系统估测的肺动脉压与心导管实测值间相关性最好（ｒ＝０．９５、０．９６）,多普勒超声技术较差（ｒ＝０．８６、０．８６）。结论：应用音频处理系统,根据改良肺动脉／主动脉血流时间间期比法可准确地无创自动估测肺动脉压。     

肝内动脉多普勒超声的检测及其临床意义

本文应用多普勒超声观察了67例正常肝脏和92例异常肝脏的肝内动脉(IHA)血流动力学的改变。结果表明正常老年人(>60岁)IHA阻力指数高于其他正常人(≤60岁)(P<0.001),慢性肝炎、肝炎后肝硬化IHA阻力指数逐渐增高(P<0.001)。原发性肝癌IHA血供增多,而血管瘤IHA无明显变化。当肝脏门静脉血供明显减少时,肝动脉血供则增多。本文认为多普勒超声检测IHA血流动力学是可行的.它能够反映出所检测血管供血区肝组织病变情况,文中还讨论了其临床应用价值。     

High-speed camera with real time processing for frequency domain imaging

We describe a high-speed camera system for frequency domain imaging suitable for applications such as in vivo diffuse optical imaging and fluorescence lifetime imaging. 14-bit images are acquired at 2 gigapixels per second and analyzed with real-time pipeline processing using field programmable gate arrays (FPGAs). Performance of the camera system has been tested both for RF-modulated laser imaging in combination with a gain-modulated image intensifier and a simpler system based upon an LED light source. System amplitude and phase noise are measured and compared against theoretical expressions in the shot noise limit presented for different frequency domain configurations. We show the camera itself is capable of shot noise limited performance for amplitude and phase in as little as 3 ms, and when used in combination with the intensifier the noise levels are nearly shot noise limited. The best phase noise in a single pixel is 0.04 degrees for a 1 s integration time.     

A simulation of transit time effects in Doppler ultrasound signals

A signal model is proposed which can be used to study frequency extraction techniques for Doppler ultrasound. The signal is based on the physics of the Doppler process and depends on a sliding window used to average a set of independent Gaussian random numbers. This window is related to the shape of the sample volume for the Doppler pulse and depends on the Doppler angle. Simulation results compare favorably with results from flow experiments in terms of the variance of the estimated Doppler shift, the shape of the power spectra and the behavior of the signals with respect to Burg autoregressive power spectra. A potential use of the signal in the study of spectral analysis techniques is presented.     

肢体动脉闭塞性疾病的彩色多普勒超声诊断

回顾性总结经彩色多普勒检查的肢体动脉闭塞性疾病２２例，其中１８例获得直接诊断依据，即病变段动脉缺乏多普勒血流信号，占８１．８２％，其结果与ＤＳＡ检查比较，差异不显著。彩色多普勒检查具有操作简单、无创伤性、无并发症等特点，是检查闭塞性动脉疾病的敏感方法，值得在临床进一步推广应用。     

二维彩色多普勒超声诊断周围动脉栓塞

本文对29例超声拟诊为周围动脉栓塞的病例进行了回顾性研究，全部病例均经手术、动脉造影或临床确诊。研究显示超声诊断周围动脉栓塞的准确率为96％、敏感性100％、血栓检出率及定位准确性分别为88％和100％，结果提示二维彩色多普勒超声具有无创、简便、快速及可重复检查的特点，可弥补动脉造影的不足。本文还对超声检测周围动脉病变时应注意的问题及其局限性进行了探讨。     

Ultrasonic signal processing for in vivo attenuation measurement: short time Fourier analysis

Short-time Fourier analysis is well suited for processing tissue echographic signals which are nonstationary. We have investigated the use of short-time Fourier analysis to provide an estimation of the echographic spectral composition as a function of time. It will be shown that the time dependence of the spectral centroid of this representation allows one to deduce easily the frequency-dependent attenuation. A simple correction of the noninvariant filtering effect due to diffraction is used to unbias the attenuation slope estimation. This new signal processing technique was first tested on simulated echographic data from a 1-D tissue model. Experimental results obtained from echo signals on a tissue-like phantom and on in vivo liver tissue show the influence of diffraction and attenuation respectively.     

川崎病急性期冠状动脉病变的多普勒超声检测及其临床意义

目的　探讨川崎病急性期的多普勒超声检测及其临床意义。方法　回顾分析 14 2例川崎病急性期的多普勒超声表现 ,并与 3 6例正常小儿的检测结果对比 ;研究川崎病冠状动脉的二维声像图、左冠状动脉前降支舒张期峰值血流速度和左心室壁的节段性运动异常。结果　川崎病急性期冠状动脉管壁及其周围组织回声异常 94%;管腔扩张2 0 %;川崎病组冠状动脉舒张期峰值血流速度增加 ,与正常组差异有显著性意义 ( 4 8.96± 8.3 8Vs 3 1.85± 2 .5 5 ,P <0 .0 1) ;川崎病急性期左心室壁运动积分指数较正常组显著增加 ( 1.16± 0 .0 9Vs 1.0 0± 0 .0 0 ,P <0 .0 1) ,室壁运动异常率达 10 0 %。结论　川崎病急性期冠状动脉病变不仅可导致冠脉结构形态、内径的变化 ,也可导致冠脉血流速度增加和心肌供血不足 ,多普勒超声可以对川崎病冠状动脉炎进行早期诊断并具有重要的临床意义 ,是诊断川崎病的一主要依据     

经颅多普勒超声对椎－基底动脉系统供血的观察

本文随机选择７２０例病人进行ＴＣＤ检测，以观察椎－基底动脉系统供血的情况。全组ＴＣＤ总异常率为８２．１％，其中高血压、心脏病、颈椎病ＴＣＤ异常率分别为９６．１％、９４．８％、８７．６％。年龄越大，异常率越高。全组血流速度异常率：ＶＡ３６．３％、ＢＡ３６．７％。频谱形态异常率：３８．４％。尽管病种不同，但各病种间ＶＡ、ＢＡ血流速度升高或降低值均相近，无明显统计学差异。ＴＣＤ检测Ｖ－ＢＡ系统血流动力学变化是一种灵敏、有效的检查方法。     

经颅多普勒超声对椎－基底动脉系统供血的观察

本文随机选择720例病人进行TCD检测,以观察椎-基底动脉系统供血的情况。全组TCD总异常率为82.1%,其中高血压、心脏病、颈椎病TCD异常率分别为96.1%、94.8%、87.6%.年龄越大,异常率越高。全组血流速度异常率：VA36.3%、BA36.7%.频谱形态异常率：38.4%.尽管病种不同,但各病种间VA、BA血流速度升高或降低值均相近,无明显统计学差异。TCD检测V-BA系统血流动力学变化是一种灵敏、有效的检查方法。     

Prolongation of TCD-enhanced Doppler signal by continuous infusion of levovist

This study evaluated the effects of two different rates of infusion of echo-contrast agents (ECA) on signal enhancement. A total of 15 patients with insufficient Doppler signal due to inadequate transtemporal acoustic bone window were examined. Signal from the middle cerebral artery was recorded during the IV infusion of Levovist (300 mg/mL). Increment of signal enhancement in dB, time to signal enhancement appearance, time to clinically useful signal enhancement appearance, and duration of clinically useful signal enhancement were assessed during two infusions at the rate of 1 and 0.66 mL/min, respectively. Increment of signal enhancement was similar at the rate of 1 and 0.66 mL/min (p = 0.4). Mean time to signal enhancement appearance and mean time to clinically useful signal enhancement appearance were not significantly different with the two rates of infusion (p = 0.9 and p = 0.3, respectively). Mean duration of clinically useful signal enhancement was significantly higher with the infusion rate of 0.66 mL/min as compared to 1 mL/min (p < 0.0001). Levovist injected at the infusion rate of 0.66 mL/min prolonged the mean duration of signal enhancement, maintaining its effectiveness.     

Arterial pulse wave velocity with tissue Doppler imaging

This paper describes a new noninvasive ultrasonic method for estimating pulse wave velocity (PWV), an important physical parameter for characterizing the elastic properties of the arterial walls. The method utilizes a relatively new color Doppler modality for measuring tissue motion (tissue Doppler imaging or TDI). In contrast to previously proposed methods, the TDI modality offers multiple recording sites along the artery that improve the PWV estimation considerably. The new PWV estimation method was evaluated through an in vitro setup consisting of an elastic vessel supplied with a pulsatile pump. The study concentrated on the effect of different system parameters controlling resolution, sensitivity and the amount of acquired data. It was shown that the system parameters have a significant effect on the PWV variance, whereas the PWV mean remains unchanged. It was also established that high temporal resolution is the most vital parameter for minimizing PWV variance. Finally, the new PWV estimation method was applied to a limited set of human carotid artery data sets, with good results.     

静注20%英脱利匹特增强动脉多普勒信号的实验研究

本文应用脉冲多普勒对５只兔子静注四种剂量２０％英脱利匹特前后腹主动脉及股动脉多普勒频谱信号进行观察，并以等剂量生理盐水为对照。结果发现：生理盐水各剂量组均未见多普勒回声强度增强。     

创伤失血性休克兔肾动脉血流改变的多普勒监测

目的　检测创伤失血性休克 3 0、60及 12 0min时 ,兔肾动脉血流多普勒频谱的改变特征。方法　实验动物分为复苏组与对照组 ,应用Acuson12 8XP 10型彩超仪 ,测定兔肾动脉在休克后不同时间段的血流参数。结果　失血性休克后肾动脉收缩期血流峰值速度 (Vmax)、舒张期血流速度 (Vmin)和平均血流速度 (Vmean)显著减低 ,随时间呈递减趋势 ,与复苏组比较差异显著 (P <0 .0 1) ,但休克后复苏组上述诸值与休克前相比变化不明显。结论　失血性休克后肾血供随时间递减 ,采用静脉输注高渗氯化钠 右旋糖酐 (HSD)可以对抗上述病理过程     

肝硬化腹腔动脉血流动力学改变的超声多普勒研究

本文应用彩色多普勒探测４２例肝硬化患者及１５例正常人脾动脉（ＳＡ）、肠系膜上动脉（ＳＭＡ）血流参数，研究肝硬化腹腔动脉血流动力学变化与上消化道出血及腹水的关系。结果表明肝硬化食管静脉曲张上消化道出血患者脾动脉阻力指数（ＳＡＲＩ）较无出血组及对照组明显增高，提示ＳＡＲＩ与肝硬化门脉高压密切相关，可作为预测食管静脉曲张上消化道出血的一项无创性新指标；此外大量腹水的出现有可能减低门脉压力，减少食管静脉曲张上消化道出血的发生     

Test signal injection for Doppler systems

Objective: To evaluate the performance of continuous and pulsed Doppler systems a test signal generator has been developed, simulating an ultrasound radio frequency signal, to be injected by induction into the front-end of an ultrasound Doppler system. Unlike for flow rigs the characteristics of the simulated signal are exactly known and under full control of the user, allowing for an objective interpretation of the test results. Methods: Under software control specific signal characteristics, e.g. ultrasound carrier frequency, clutter frequency, amplitude of clutter signal with respect to Doppler signal amplitude, Doppler signal-to-noise ratio, mean Doppler frequency, shape and width of the Doppler spectral distribution, and its time-dependent behavior can be set and varied. Results: A software package was developed to manipulate the relevant characteristics of the radio frequency signal and to drive a PC compatible plug-in card for signal generation. To illustrate the applicability of the Doppler signal generator some specific examples will be discussed. Conclusion: The proposed test signal generator allows for a variety of Doppler test procedures under controlled and realistic conditions.     

肌电控制及肌电信号的分析处理

肌电信号是一种与肢体运动直上关的生理电活动，它已成为人－机仿生系统理想的控制信号源。肌电控制系统动作自然、仿生性能好。本文以肌电假肢为例，论述了肌电控制的实现方法，并系统地介绍、评价了参数模型法、人工神经网络等时域和频域体表肌电信号分析处理技术。     

多普勒超声心动图对动脉血管吻合术疗效评估的应用

目的：评估动脉血管吻合术的疗效。方法：应用多普勒超声心动图对７例桡动脉、２例尺动脉吻合术疗效进行观察,同时检测健侧桡、尺动脉。以吻合口处血管内径及血流动力学指标作为疗效评估指标。结果：７例桡动脉收缩期峰值血流速度均较健侧降低,而时间平均血流速度、血流量及血管内径无明显差异。２例尺动脉血管内径较对侧减小,血流频谱低平。结论：多普勒超声心动图是评价动脉血管吻合术疗效的一种无创、简便、可靠的检查方法。     

双功能超声检测输尿管结石患者肾内动脉阻力指数

采用双功能超亏检测３２例输尿和结石患者和３２例正常人肾内动脉阻力指数、结果表明：尿管结石患者的患肾ＲＩ显著高于健肾和正常人肾脏的ＲＩ，患肾与健肾ＲＩ差值较正常人双肾ＲＩＤ显著增高。