Quantitative assessment of the common femoral to popliteal arterial segment using continuous wave Doppler ultrasound

The common femoral to popliteal segments of 123 patients with radiologically confirmed arterial disease have been compared with those of 43 volunteers apparently free from disease. The comparisons have been based upon parameters derived from Doppler-shifted, continuous wave ultrasound.Simultaneous recordings of the Doppler signal were made from over the common femoral artery and the popliteal artery; these were analyzed subsequently to reveal variations of maximum frequency with time. Fifteen parameters were obtained from each segment. Of these the Pulsatility Index (P.I.) the Damping Factor(Δ), the pulse wave transit time(TT) the rise time ratio(RTR) from each segment were examined in detail. The Doppler results from the patient groups were compared also with the findings from arteriography.On the basis of these comparisons it was found that the RTR was simpler to measure than other more commonly used parameters such as Pulsatility Index and at least as sensitive for the differentiation between severe arterial disease and the mildly affected or normal state. However, none of these parameters was sufficiently sensitive to distinguish between mild to moderate disease and normal.     

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.     

M型超声和脉冲多普勒超声检测外周血管的对比研究

目的 检测不同节段外周血管M型波形和脉冲多普勒血流频谱时间间隔的差异性，探讨超声评价外周血管压力和血流传导的关系。方法 35例健康成人，23例冠心病患者，应用M型超声和脉冲多普勒超声扫查主动脉（AO）、颈动脉（RCCA）、腋动脉（RAA）、肱动脉（RHA）、桡动脉（RRA）、股动脉（RFA）、腘动脉（RPA），获得M型曲线和多普勒血流频谱，同步连接心电图，计算Q波起始点与M型曲线波形起始点的时间间隔（ΔT1）以及Q波起始点与血流频谱起始点的时间间隔（ΔT2）。结果 健康成人脉冲多普勒方法检测上述动脉时间间隔增长速度RCCA/AO、RAA/AO、RHA/AO、RRA/AO、RFA/AO、RPA/AO，较M型超声方法检测值为大，上述各值比较均有显著性差异（P〈0.05），冠心病患者脉冲多普勒方法和M型超声检测上述动脉时间间隔增长速度无明显差异性（P〉0.05）。结论 健康成人M型波形时间间隔增长速度快于脉冲多普勒时间间隔增长速度，冠心病患者两种时间间隔增长速度无明显差异性，可能与动脉僵硬度有关。     

Influence of spectral broadening on continuous wave Doppler ultrasound spectra: a geometric approach

A model is presented that enables the detailed effects of spectral broadening to be calculated for a continuous wave (CW) Doppler system by using geometric boundary arguments. The model assumes a uniform distribution of isotropic scatterers and treats the transmitter and receiver crystals as incremental sources and receivers. Detailed results for rectangular and circular geometries are presented in order to provide a physical understanding of the manner in which spectral broadening arises. Results are given for the circular geometry, to illustrate the manner in which the received spectrum is affected by the transducer size and distance from the vessel.     

Duplex scanning with continuous wave Doppler for carotid disease

Duplex scanning with the use of continuous wave Doppler instrumentation was used for the evaluation of carotid disease and compared to angiography. In twenty such patients 100% accuracy for diagnosis of total occlusion by Duplex scanning with continuous wave Doppler, was obtained. The sensitivity for those patients with 50%-99% stenosis was 92% and for those patients with 20%-49% stenosis was 75%. The overall accuracy for this diagnostic test for all groups of stenosis was 85%. This compares favorably with other noninvasive vascular techniques and is felt to be an accurate and useful technique for the detection of carotid stenosis. Several advantages of this technique are pointed out.     

Breast examinations with continuous wave and color Doppler.

Continuous wave Doppler has been used for many years to characterize malignant breast lesions. With continuous wave Doppler pencil probes, operating at frequencies between 8 and 10 MHz, 94% of the carcinomas have shown abnormal vascularity. Flow assessment with continuous wave Doppler alone is only possible in palpable lesions. We have improved the diagnostic accuracy by combining continuous wave Doppler and B-mode ultrasound which allows for flow detection in non-palpable lesions. This procedure is rather complicated, because of sound interference, and requires a good deal of experience.Ultrasound equipment with color flow mapping has been available for several years. However, during the last 3 years, the sensitivity of the instruments has been improved, allowing the detection of flow in microscopic vessels which are not visible in B-mode scanning. Evaluation of this method is difficult, as the sensitivity of color Doppler equipment shows remarkable variations.In order to evaluate the capability of color Doppler for investigation of abnormal blood flow in breast malignancies, we examined 120 symptomatic women using different types of equipment and compared the findings to those of continuous wave Doppler. In ten of 44 carcinomas, no color flow signals were found. However, continuous wave Doppler showed low vascularity in all of these ten false-negative cases. Among the remaining patients with benign disease, no false-positive reports were made. The major difficulty in flow assessment with color Doppler was the heterogeneous vascularity of breast malignancies. When a low Doppler frequency (相似文献   

Comparison of umbilical artery flow velocity waveform indices as measured by continuous wave Doppler ultrasound

This study examines four methods, automated and manual, of calculating the pulsatility index (PI) of fetal umbilical artery flow velocity waveforms (FVW) and compares these values to the resistance index (RI), the A/B ratio, and the degree of absence of end diastolic frequencies. The FVWs were obtained by the Doptek continuous wave Doppler ultrasound. All of the maximum envelope indices had significant correlations; a highly significant difference was found between the automated and the manual methods of determining PI. When PI was measured manually, there was a better correlation between the A/B ratio, RI, and degree of absence of end diastolic frequencies than when the automated methods were used.     

Quantification of ultrasound contrast agent response: comparison of continuous wave Doppler and power Doppler to backscattered radiofrequency data.

Our goal was to compare two quantification methods of ultrasound contrast agents available in clinical practice [continuous wave Doppler intensity (CWDI) and power Doppler intensity (PWDI)] to the reference technique (radio-frequency analysis) with a simple recirculating flow phantom using a renal dialysis cartridge. Measurements were made at different doses of perflenapent emulsion and BR1. Cineloops of power Doppler images were recorded using a clinically available ultrasound unit (HDI 3000). Simultaneously, integrated backscatter (IBS) was measured by analysis of radiofrequency signals, whereas Doppler signal intensity was measured with a continuous wave Doppler device. A linear relationship was found between CWDI and IBS and between PWDI and IBS when R(2) was calculated for each pair of parameters injection-by-injection. Results are summarized by the average R(2) for all injections between CWDI and IBS (BR1: R(2) = 0.93 +/- 0.05, perflenapent emulsion: R(2) = 0.94 +/- 0.03) and between PWDI and IBS (BR1: R(2) = 0.88 +/- 0.07, perflenapent emulsion: R(2) = 0.79 +/- 0.09). However, for all data obtained from all different injected doses and for both contrast agents, there was considerable variation of CWDI and PWDI values measured for a given value of IBS. In conclusion, for a fixed microbubble population, CWDI and PWDI can be proposed for quantification of USCA. However, their important variations observed at each dose make it difficult to link a single value of PWDI or CWDI or IBS to a single microbubble distribution composition.     

Doppler assessment of the normal early fetal circulation.

Combined transvaginal and transabdominal Doppler ultrasound allows recording of fetal intra- and extracardiac flow velocity waveforms in late first- and early second- trimester pregnancies. At 10-12 weeks, end-diastolic flow velocities were always absent in the fetal descending aorta and umbilical artery, but were present in over half of the intracerebral artery waveforms. The pulsatility index in the three vessels decreased significantly with advancing gestational age, suggesting a reduction in fetal and umbilical placental vascular resistance. Peak velocities during atrial contraction (A-wave) were nearly twice as high as those during early diastolic filling (E-wave), reflecting low ventricular compliance. Continuous forward flow in the umbilical vein was associated with a pulsatile systolic and diastolic forward flow in the ductus venosus. Retrograde flow was only present in the inferior vena cava.     

Measurement of pulse wave velocity using pulse wave Doppler ultrasound: comparison with arterial tonometry

Pulse wave velocity (PWV), the speed of propagation of arterial pressure waves through the arterial tree, is related to arterial stiffness and is an important prognostic marker for cardiovascular events. In clinical practice PWV is commonly determined by arterial tonometry, with a noninvasive pressure sensor applied sequentially over carotid and femoral arteries. The electrocardiogram (ECG) is used as a timing reference to determine the time delay or "transit time" between the upstroke of carotid and femoral pulse waveforms. Commercially available vascular ultrasound scanners provide a pulsed wave (PW) Doppler velocity signal, which should allow determination of carotid-femoral transit time and hence PWV. We compared carotid-femoral PWV measured by tonometry and by PW Doppler ultrasound (Seimens, Apsen scanner with 7 MHz linear transducer) in asymptomatic subjects (n = 62, 26 male, aged 21 to 72 y). To test for intra-subject and inter-observer variation, ten subjects were scanned by one observer on two occasions 2 wk apart and by two observers on same day. PWV by tonometry ranged from 5.3 to 15.0 m/s. There was no significant difference between mean values of PWV obtained by the two techniques (mean difference: 0.3 m/s, standard deviation of difference: 1.5 m/s), which were closely correlated (r = 0.83). The coefficient of variation for repeated measures on the same subject by the same observer was 10.1% and the inter-observer coefficient of variation was 5.8%. These results suggest a commercial ultrasound scanner can be used to measure PWV, giving results that are reproducible and closely correlated with those obtained by arterial tonometry. (E-mail: ben_yu.jiang@kcl.ac.uk).     

彩色多普勒超声在检测脐-胎盘循环状况中的应用

应用彩色多普勒超声血流显像系统检测胎儿脐动脉、大脑中动脉及孕妇子宫螺旋动脉等主要血管的血循环变化,通过测量其收缩期峰值流速与舒张期流速比值、阻力指数、搏动指数3项参数,能较好地反映胎盘循环的病理生理变化.脐动脉血流多普勒测值参数收缩期峰值流速与舒张期流速比值、阻力指数、搏动指数与孕周呈高度负相关:胎儿大脑中动脉血流各检测值均随孕龄增长而呈下降趋势:妊娠后孕妇子宫螺旋动脉的阻力指数、搏动指数低于妊娠前.多项指标联合运用可提高对围产儿不良结局预测的准确性与可靠性.     

Review article: Non‐invasive assessment of cardiac output with portable continuous‐wave Doppler ultrasound

Cardiac output is considered an important parameter when assessing the cardiovascular status of a critically ill patient. Both non‐invasive (e.g. bioimpedance, echocardiography) and invasive methods (Swan Ganz catheter) have been used to measure cardiac output. The ultrasonic cardiac output monitoring device provides a new method of non‐invasively assessing cardiac output in various clinical settings. The ultrasonic cardiac output monitoring device was introduced clinically in 2001, and appears to be a promising adjunct in the assessment of the cardiovascular state in a variety of patient cohorts. In this short review article, we will introduce this new technique, discuss the required skills and compare it with methods already in use. In particular, a critical comparison with the ‘gold standard’, the invasive measurement of cardiac output with the pulmonary artery catheter, will be given.     

A measurement system for continuous wave ultrasound fields

A measurement system for evaluating ultrasound fields is presented. The system utilizes a PVDF hydrophone and a mechanical scanning device. For continuous wave (CW) ultrasound, a high sensitivity is achieved by using a narrow band technique. The high sensitivity is demonstrated in a recording of the beam profile from an air transducer. Recordings from fetal Doppler equipment shows that, due to interference between the multiple transmitters, a high spatial resolution is needed in the field measurements in order to obtain correct values for peak intensities.     

Systemic assessment of fetal hemodynamics by Doppler ultrasound

The aim of our study was to investigate the parameters of fetal circulation of normal pregnancies and their relationship to fetal cardiac output. We performed a cross-sectional study of 315 normal singleton pregnancies between 20 and 40 weeks' gestation without fetal chromosomal or structural malformations. After follow-up to delivery, 212 patients who fit all the criteria were enrolled for final analysis. Blood flow velocity waveforms were obtained from the tricuspid and mitral ventricular inflow, ascending aorta (AAO), pulmonary artery (PA), middle cerebral artery (MCA), renal artery (RA), umbilical artery (UA), descending aorta (DAO), inferior vena cava (IVC) and ductus venosus (DV) using duplex (real-time Doppler) ultrasound (US) scanner. The peak velocity of DV, AAO, PA and MCA were also obtained. At the intracardiac level, the ratio of peak flow velocity of E wave to peak flow velocity of A wave (E:A ratio) of mitral valve (MV) increased more rapidly than tricuspid valve (TV) E:A ratio. For the great vessels, aortic peak velocity remained higher than the pulmonary peak velocity with advancing gestation. The cardiac output closely correlated to the cardiac compliance and flow resistance indices at arterial and venous level. The acceleration time in the fetal arteries increased with advancing gestation in AAO, PA, MCA and DAO, but it decreased in RA and kept constant in UA. In addition, the acceleration time of UA was unrelated to cardiac output. The changes of the fetal intracardiac, arterial and venous impedances were remarkable through the gestation and related to cardiac output. Fetal cardiac output correlated well with the changes of arterial resistance, except with the DAO. The ventricular compliance increased with advancing gestation, especially in the left side, and was highly related to the change of cardiac output. The acceleration time in major arteries positively correlated with the gestational age and cardiac output, except in UA and RA; this indicates the difference of the changes of mean arterial pressure in uteroplacental circulation, fetal organs and great vessels. In conclusion, the fetal cardiac output correlated well with the ventricular compliance and was influenced by both hemodynamic changes in peripheral resistance and mean arterial pressure.     

Use of Doppler ultrasound in leg ulcer assessment

Adequate patient assessment is the most important element of chronic wound management, and the use of holistic techniques enables practitioners to make informed clinical judgements. Doppler ultrasound is integral to the holistic assessment of leg ulcers. This article reviews the procedure for measuring ankle/brachial pressure indices using Doppler ultrasound and outlines various diagnostic tests that employ the Doppler principle.     

多普勒超声评价克罗恩病活动性的价值

目的 探讨多普勒超声观察肠系膜上动脉及病变段肠壁内动脉在评估克罗恩病(CD)活动性中的价值。 方法 根据Harvey-Bradshaw指数(HBI)将33例CD患者分为活动组(n=16)和静止组(n=17),采用彩色脉冲多普勒超声定量测量肠系膜上动脉血流,能量多普勒超声对病变段肠壁内血流进行半定量Limberg评分,评价疾病活动性,比较两组间多普勒超声参数,并将其与相应C反应蛋白(CRP)及HBI进行相关分析。 结果 肠系膜上动脉舒张末期流速、阻力指数在活动组与静止组之间的差异有统计学意义(P均<0.05)。两组间病变段肠壁内血流Limberg评分差异有统计学意义(P<0.001)。舒张末期流速与CRP呈正相关(r=0.602,P<0.001),与HBI无显著相关性;阻力指数与CRP(r=－0.676,P<0.001)、HBI(r=－0.415,P=0.020)呈负相关;肠壁血流Limberg分级与CRP(r=0.587,P<0.001)、HBI(r=0.498,P=0.003)相关性较好。 结论 多普勒超声可作为评价CD活动性的可靠工具,指导临床采取合适的治疗措施,对病变随访和疗效监测也具有重要意义。