Measurement of aortic blood velocity in acute myocardial infarction by Doppler ultrasound

Aortic blood velocity was measured by a transcutaneous continuous wave Doppler technique in thirty-five patients with proven acute myocardial infarction. Measurements were made on the first and seventh day following admission to hospital. Group I comprised 21 patients who had sustained a first myocardial infarction of moderate size, uncomplicated by hypoperfusion. Group II comprised 14 patients who had had a large rise in cardiac enzymes, a previous myocardial infarction or were clinically hypoperfused. The mean value for peak aortic velocity for Group I on Day 1 was 88±12.9 cm/s. This was significantly lower than the mean value of 101.8±23.1 cm/s for a group of 85 normal subjects. By Day 7 the mean value for Group I of 105.1±19.8 cm/s was not significantly different from normal. For Group II patients on Day 1 the mean value for peak aortic velocity was 67.9±11.7 cm/s and was significantly lower than that for both Group I and the normal group. By the seventh day the mean value for Group II was 76.5±17.1 cm/s which was not significantly different from Day 1.     

Spatial and temporal resolution of aortic Doppler blood velocity signals in normal human subjects

We have used digital, microcomputer-based methods for the numerical analysis of pulsed, range-gated, ultrasonic Doppler blood velocity signals recorded with an axially aimed transducer from the ascending aorta of normal subjects. We investigated the spatial, temporal and amplitude resolution of our methods for recording and analysis, comparing aortic signals with test signals from a sine wave function generator. The spatial resolution of our system was found to be adequate in spite of the use of a relatively large sample volume. The temporal resolution was significantly influenced by the rate of change of velocity which affected the results of discrete fast Fourier transform analysis. The rate of increase in aortic blood velocity at the start of ejection was linear, following an initial jump in velocity. The amplitude resolution was affected by fluctuations in the amplitude of the Doppler signals. We conclude that our methods do not exaggerate the bluntness of the aortic velocity profile or the linearity of the increase in blood velocity at the start of left ventricular ejection.     

Ultrasonic measurement of fetal blood velocity wave form as a secondary diagnostic test in screening for intrauterine growth retardation

Based on routine fetometry screening at 32 weeks of gestation, 80 out of 3226 singleton pregnancies were suspected of intrauterine growth retardation (IUGR) and 72 of them were subjected to repeated fetal blood flow measurements by Doppler ultrasound for evaluation of the fetal condition. The maximum blood velocity wave form recorded from the fetal descending aorta and umbilical artery was classified as normal or abnormal depending on the presence or absence of positive end-diastolic blood flow. Compared to the pregnancies with normal fetal blood flow, the group of 30 pregnancies with abnormal blood flow patterns had significantly more pregnancy complications and more operative deliveries for fetal distress. In the latter group, all newborns but one were small-for-gestational age and had low 1-min Apgar scores more frequently. Fetal blood flow measurements have a good capacity for predicting unfavorable fetal outcomes and can be recommended for clinical use. The combination of ultrasound screening and Doppler blood flow measurement has reduced the number of pregnancies requiring intensive surveillance.     

二维及多普勒超声心动图诊断主动脉窦瘤破裂的评价

15例主动脉窦瘤破裂经二维及多普勒超声心动图诊断。所有病例均得到心血管造影或手术证实。本组超声诊断的符合率为100％。本文讨论了主动脉窦瘤破裂至不同腔室的最佳切面及声像图表现。同时认为,详细的病史资料采集,超声的全面探查,增加右心声学造影是提高诊土窦瘤破裂合并畸形准确率的重要手段。     

Doppler ultrasound waveforms in the fetal umbilical artery: quantitative analysis technique

Doppler ultrasound waveforms from the fetal umbilical artery were analyzed by a new quantitative technique. Normal pregnancy and cases of fetal growth failure were considered. Data from the spectrum analyzer were dumped to a microcomputer, the velocity waveforms calculated and a representative waveform obtained by ensemble averaging. This curve was then fitted by a 4-parameter analytic function. We introduce R, the relative flow rate index, which measures the ratio of the average flow rate before the systolic peak to the average rate during the remainder of the cardiac cycle. In cases of fetal growth failure this ratio was significantly greater than in normal pregnancy. Other new quantities defined are the normalized systolic decay time index and the constant flow ratio. The AB ratio was also calculated. Fetal growth failure has been associated with raised placental resistance. We suggest that the fetus can initially compensate for this by increasing cardiac contractility. This can be seen by interpreting the R and AB values together. Our analysis technique enables the waveform to be efficiently described, and provides useful diagnostic information about placental function and fetal wellbeing.     

Three-dimensional cross-sectional velocity distribution in the ascending aorta in cardiac patients

Summary. Knowledge of the distribution of velocities across the ascending aorta is important for measurements of cardiac output; for understanding the function of normal and diseased valves and for the evaluation of prosthetic valves. The aim of this study was to investigate, in detail, the spatial distribution of axial velocities in the human ascending aorta, covering a nearly complete cross-section of the lumen in a time continuous modus. During open-heart surgery, blood velocities in the ascending aorta were mapped in 10 patients. All patients had aortic valves with no significant clinical evidence of disease. Pulsed Doppler ultrasound technique was used to measure blood velocity using an intraluminal probe with a 1 mm, 10 MHz crystal connected to a position-sensitive device. The distribution of blood velocity in the aorta 6–8 cm above the valve was characterized by a skewed and irregular peak systolic flow, with maximum velocity posteriorly. There was a positive correlation (n=0.854, P < 0.002) between the maximum skewness slope and the stroke volume. Significant retrograde flow was recorded in all patients in the left posterior part of aorta in late systole and early diastole. The rotation of the point of maximal velocity was anticlockwise in six patients, clockwise in three and alternating in one. The present study shows that there is a considerable individual variation in the velocity distribution in the ascending aorta, with no plane symmetric features, and that large sampling volumes are required for reliable estimates of mean velocity.     

经颅多普勒检测主动脉瓣返流患者脑动脉血流变化

观察主动脉瓣返流患者脑动脉血流动力学变化。方法：选取观察组４６例,对照组５０例,采用彩色超声心动图、经颅多普勒分别观察心脏主动脉瓣返流性质和程度及其他情况,观察脑动脉血流动力学各项指数。结果观察组４６例,其中单纯主动脉瓣返流３４例,主动脉瓣返流伴二尖瓣病变１２例;对照列。     

多普勒超声检测主动脉瓣返流患者颈动脉血流变化

本文旨在观测主动脉瓣返流患者颈动脉血流动力学变化。观察组42例，其中主动脉瓣返流30例，主动脉瓣返流伴二尖瓣病变12例；正常组42例。正常顿总动脉频谱形态呈三峰形，舒张早期可有反向频谱，Vr10．8±3．6cm／s，△T／T比值＜1／10。主动脉瓣返流患者颈动脉收缩期V1、AC、DC均显著增大；舒张期可出现“返流频谱”，即△T／T比值≥1／10。根据△T／T比值可大致分级主动脉瓣返流程度，轻度返流：△T／T比值＜1／4或正常；中度；△T／T比值1／4～1／2；重度：△T／T比值＞1／2；可作为分级主动脉瓣返流程度的一种简便辅助方法。对于临床听不到杂音的主动脉瓣返流患者，颈动脉“返流频谱”可作为有用线索，提示病变存在。本文还探讨了收缩期颈动脉血流动力学变化。     

彩色多普勒超声在产前胎儿畸形诊断中的应用价值

目的 探讨彩色多普勒超声诊断在产前胎儿畸形诊断中的应用价值.方法 选择2007年11月至2010年12月在我院进行检测分娩的孕妇2764例,运用彩色多普勒超声检测仪进行产前胎儿畸形诊断检测,最终确定检测结果,分析多普勒彩色超声检测的实际应用效果和检测准确率.结果 2764例孕妇中,共有13例经彩色多普勒超声诊断仪检测发现畸形,经证实13例畸形胎儿均检测正确;有2例畸形胎儿未检出,分别是先天性心脏病1例和胸腔畸形1例.彩色多普勒超声检测仪的检测准确率为86.67％.结论 多普勒彩色超声检测具有准确率高、检测方法简便、检测费用合理等优点,已经成为产前胎儿畸形诊断的主要方法,各医疗机构可根据情况选用不同的型号进行产前胎儿畸形诊断.     

On the measurement of the mean velocity of blood flow over the cardiac cycle using Doppler ultrasound

A number of modern duplex scanners now have facilities for determining volumetric blood flow through intact vessels. The methods these machines use to arrive at an answer must presuppose a number of conditions which may not be met in practice. This paper examines the effect that nonuniform insonation of the target blood vessel (using continuous wave or wide-gate pulsed ultrasound) has on the mean velocity, as determined using mean, root mean square (RMS) and maximum frequency processors. It is shown that for a given beam/vessel geometry the error is dependent only on the shape of the mean component of the velocity profile which, depending on the arterial site, may be flat, parabolic or intermediate. Mean processors may overestimate the mean velocity of established flow by up to 33%, but this could be turned to advantage when it is impracticable to insonate a vessel uniformly. Maximum frequency processors are of value when either plugflow or fully established flow of low pulsatility is present in the target vessel. In the first case the mean flow is the same as the maximum flow, while in the second the mean flow is half the time averaged maximum flow, irrespective of the size and shape of the ultrasound beam. RMS processors are probably best avoided in volumetric flow measurement applications.     

多普勒超声检测胎儿心脏机械性PR间期的临床意义研究

目的应用多普勒超声技术测量胎儿心脏机械性PR间期并探讨其临床意义。方法选取经胎儿超声心动图检出的83例疾病组胎儿,分别为先天性心脏病及心律失常。正常对照组为100例中、晚孕胎儿。应用彩色多普勒引导脉冲多普勒取样容积记录左心室流入道及流出道血流频谱,测量从舒张期二尖瓣A峰起始至收缩期主动脉射血起始的心房到心室的传导时间(PR间期),并同时测量收缩期主动脉射血起始至二尖瓣A峰起始的时间(VA间期)。结果 83例疾病组胎儿中先天性心脏病69例,心律失常12例,双胎输血综合征1例(双胎儿)。其中54例多普勒超声测量PR间期延长(131～220ms),并检出自身免疫性抗体阳性和弱阳性5例。正常对照组100例的中、晚孕孕妇均无自身免疫系统疾病,并经超声排除胎儿先天性心脏病、心律失常及其他胎儿异常,多普勒超声测量PR间期值均≤130ms。两组PR间期、VA间期比较差异有统计学意义(P0.01)。结论本研究结果表明,除孕妇患自身免疫性疾病可引起胎儿传导系统受损外,胎儿患先天性心脏病、心律失常等疾病时,其窦房结、房室结传导功能的易损性明显高于正常胎儿。其影响因素与心脏解剖结构异常和传导系统发育不良的相关性有待进一步研究。     

Maternal breath-holding and the valsalva maneuver: methods to overcome fetal breathing movements during Doppler sonography

Fetal breathing movements (FBM) hinder Doppler measurements in the fetus. The aim of the present study was to establish whether FBM are overcome by the mother holding her breath for a few seconds or performing the Valsalva maneuver (VM). This prospective study included a group of 120 consecutive patients showing FBM. In 78 patients (65%), FBM were observed only at the beginning of the examination and then stopped spontaneously. In the other 42 patients, FBM were still present during and at the end of the general examination. These patients were considered for the evaluation. In a first step, the mother was asked to hold her breath for 5 s. If FBM continued, the procedure was repeated. If this also failed, the Valsalva maneuver was performed. In the presence of fetal apnea, flow velocity measurements were taken from the umbilical artery. Nine patients (21%) halted FBM with the first attempt at maternal breath-holding, four patients (10%) with the second attempt and 22 patients (52%) on using the VM. FBM was arrested within a maximum of 94 s after breath-holding or the VM. No reaction to any of the procedures was observed in seven patients (17%). Breath-holding alone or in combination with the Valsalva maneuver has been shown to be effective in overcoming the problem of FBM during prenatal Doppler examination in most cases.     

医学超声Doppler技术中位置－速度的检测约束和血流（横向）速度剖面的获得

本文提出了医学超声Ｄｏｐｐｌｅｒ技术中位置和速度检测的约束问题，并从几个方面分析了产生这种约束的原因。作为应用和进一步的理解，文中还介绍了一种避免位置和速度约束关系的血流（横向）速度剖面的估计方法，最后对医学超声多普勒技术中位置和速度的检测约束及血流速度剖面的获得进行了讨论。     

Fetal cardiac arrhythmias and their effect on volume blood flow in descending aorta of human fetus

Using a two-dimensional linear array real-time and pulsed Doppler ultrasound system, volume blood flow measurements were made in 86 normal pregnancies, seven cases of fetal bradycardia, and seven cases of fetal tachycardia at the lower thoracic level of the fetal descending aorta. During fetal cardiac arrhythmias, volume blood flow was maintained within the normal range until the heart rates reached around 50 bpm and 230 bpm, after which the volume blood flow diminished. The changes observed suggest that the Frank-Starling mechanism is functional in the fetal myocardium and demonstrate the stability of the fetal circulation.     

多普勒超声心动描记术检测胎儿机械性QT间期

目的 探讨多普勒超声心动描记术在测量胎儿机械性QT间期中的应用价值。 方法 对胎儿心脏无异常的早孕期、中孕期和晚孕期孕妇各100名行胎儿多普勒超声心动描记术检查。记录左心室流入道及流出道血流频谱,测量机械性QT间期,即自二尖瓣舒张期A峰结束至下一个舒张期E峰开始的时间,同时测量胎儿心率。 结果 胎儿机械性QT间期和心率呈正态分布,早孕、中孕和晚孕组胎儿机械性QT间期均值的95%可信区间分别为225.25~231.21 ms、241.21~248.79 ms和253.23~259.45 ms;不同孕期组间胎儿机械性QT间期和心率的差异均有统计学意义(P均<0.01);胎儿机械性QT间期与孕周呈正相关(r=0.499,P<0.01),胎儿心率与孕周呈负相关(r=-0.628,P<0.01)。 结论 应用多普勒超声心动描记术检测胎儿机械性QT间期简便易行,图像清晰且重复性好,可为临床诊断胎儿心律失常提供重要依据。     

组织多普勒技术评价妊娠期糖尿病胎儿心脏作功指数

目的探讨妊娠期糖尿病对胎儿心脏结构和功能的影响.方法妊娠期糖尿病患者血糖控制不良者18例,血糖控制良好者17例,正常对照组70例.每例妊娠过程中至少进行3～4次胎儿超声心动图检查,测量胎儿心脏室壁厚度,应用组织多普勒技术计算胎儿心脏的整体作功指数(Tei指数).结果妊娠期糖尿病血糖控制不良组胎儿心脏室壁厚度及左、右心Tei指数均高于其他两组.血糖控制良好组胎儿心脏左、右心Tei指数高于正常组,室壁厚度与正常组无差异.结论妊娠期糖尿病患者胎儿心脏的结构与功能受到不同程度的损害.     

彩色速度成像及脉冲多普勒测量正常人颈动脉流速对照

目的：探讨彩色速度成像（ＣＶＩ）测量血流速度的准确性。方法：对６０位正常人分别用ＣＶＩ和脉冲多普勒方法测量左右颈动脉的最大血流速度（Ｖｍａｘ）和阻抗系数（ＲＩ）并进行统计学处理。结果：两种方法测量女性左侧颈动脉Ｖｍａｘ分别为７７４４±１８５１ｃｍ／ｓ、８３６０±１９９０ｃｍ／ｓ（ｒ＝０９５９）,ＲＩ分别为０７３３±００５４、０７１９±００４７（ｒ＝０９０４）;右侧颈动脉Ｖｍａｘ分别为７３９５±１９１８ｃｍ／ｓ、７９４９±１８２２ｃｍ／ｓ（ｒ＝０９５５）,ＲＩ分别为０７３６±００５８、０７３４±００６１（ｒ＝０９２７）;男性左侧颈动脉Ｖｍａｘ分别为９４１７±２４３５ｃｍ／ｓ、９７７６±２４０８ｃｍ／ｓ（ｒ＝０９７１）,ＲＩ分别为０７５９±００６４、０７４３±００５７（ｒ＝０９１０）;右侧颈动脉Ｖｍａｘ分别为９１９６±２３８９ｃｍ／ｓ、９７９６±２４９７ｃｍ／ｓ（ｒ＝０９５４）,ＲＩ分别为０７８９±００５２、０７８３±００５５（ｒ＝０９０２）。结论：两种方法对血流Ｖｍａｘ及ＲＩ的测量均相关很好（ｐ＜０００１）,证实了ＣＶＩ技术测量     

Reproducibility of fetal cardiac flow velocity waveforms at atrioventricular level

Reproducibility of flow velocity waveform recording and analysis was studied at fetal atrioventricular level (mitral and tricuspid valve) in 25 normal pregnancies. The flow velocity parameters studied were peak-E wave velocity, peak-A wave velocity and time-averaged velocity. In each patient, two consecutive measurements were performed (time delay, 15 min) and of each measurement two hardcopies were analyzed. A high reproducibility was achieved for all parameters studied; the coefficients of variation between readings of hardcopies were <2% and the coefficients of variation between tests within patients were -4%.     

Method for the measurement of the maximum Doppler frequency

This paper describes a method for detection of the maximum Doppler frequency from a histogram of Doppler signals (HDS). The performance of the system is described, and its behavior in analysis of noise signals that have known lower and upper cut off frequencies is discussed. Experimental investigations show that the device correctly measures the maximum frequency envelope and can be useful in evaluating the maximum flow velocities in the blood circulation system.     

A continuous wave Doppler ultrasound method of recording fetal breathing in utero

Intra-uterine fetal breathing can be measured using 2 MHz continuous wave Doppler ultrasound to monitor the fluctuations in venous return which are associated with the pressure changes induced by fetal breathing activity. This article describes the technique for locating the transducer on the maternal abdomen and the sounds that are heard, together with the instruments necessary for recording, processing and displaying the signal.