Study of blood flow parameters measured in femoral artery after exercise: correlation with maximum oxygen uptake

To study the recovery periods of blood flow parameters in muscles after anaerobic exercise, instantaneous and mean blood flow velocity curves were recorded in the femoral artery in 22 sportsmen at rest and during the first 4 min of recovery after exercise (Ruffier-Dickson test). A flat ultrasonic probe connected to a Doppler system (Flow-Tester) was fixed on the skin at the level of the common femoral artery. From Doppler recordings, we calculated periods of recovery (return to baseline) of femoral blood flow velocity (FBFV RP), heart rate (HR RP) and femoral stroke distance (FSD RP). Also, Ruffier-Dickson index (RDI), VO(2)max in mL/kg(-1)/min(-1) and number of training hours were determined. We observed a high correlation between FBFV RP and VO(2)max (p = 0. 0002), and significant correlation between FSD RP and VO(2)max (p = 0.0238) and RDI (p = 0.0451). In conclusion, there is a excellent correlation between blood flow velocity recovery period in femoral artery after moderate exercise and VO(2)max in high-level sportsmen. The method of testing is simple and based on conventional Doppler technique. It can be used for the follow-up of training levels in sportsmen.     

多普勒取样容积变化对外周血管血流定量影响的实验研究

为探讨不同大小多普勒取样容积（ＳＶ）对外周血管血流定量影响，我们以血泵流率为标准，选择内径５．０ｍｍ模拟血管和溶液为肝素化人全血，ＳＶ大小为１．５ｍｍ、５．０ｍｍ和１０．０ｍｍ，进行体外模拟脉动血流速度频谱实验。结果当流率为３００ｍｌ／ｍｉｎ和５００ｍｌ／ｍｉｎ时，不同大小ＳＶ多普勒血流量测量值不同，ＳＶ１．５ｍｍ与５．０ｍｍ和１０．０ｍｍ，血流量测量值相差显著（Ｐ＜０．０１），而ＳＶ５．０ｍｍ与１０．０ｍｍ间相差不显著（Ｐ＞０．０５）。建议在外周血管血流定量检查时，正确选用ＳＶ大小，以便减小测量误差。     

A New Echocardiographic Method for Identifying Vortex Flow in the Left Ventricle: Numerical Validation

A new mathematical method for estimating velocity vectors from color Doppler datasets is proposed to image blood flow dynamics; this method has been called echodynamography or vector flow mapping (VFM). In this method, the concept of stream function is exploited to expand a 2-D distribution of radial velocities in polar coordinates, observed with color Doppler, to a 2-D distribution of velocity vectors. This study was designed to validate VFM using 3-D numerical flow models. Velocity fields were reconstructed from the virtual color Doppler datasets derived from the models. VFM captured the gross features of flow structures and produced comparable images of the distribution of vorticity, which correlated significantly with the original field (for velocity magnitudes, standard error of estimate = 0.003 to 0.007m/s; for vorticity, standard error of estimate = 0.35 to 2.01/s). VFM may be sensitive for depicting flow structures derived from color Doppler velocities with reasonable accuracy. (E-mail: t.uejima@nifty.ne.jp)     

Fetal hemodynamics evaluated by Doppler velocimetry in the second half of pregnancy

The objective of our study was to assess fetal hemodynamics by Doppler velocimetry during the second half of pregnancy. We carried out a longitudinal study on 33 normal fetuses between the 22nd and 38th weeks of gestation. Doppler velocimetry was performed in the aorta, suprarenal (SRA) and infrarenal (IRA) segments, middle cerebral artery (MCA) and umbilical artery (UA), on the basis of fetal peak systolic velocity (SV), end-diastolic velocity (DV) and resistance index (RI). We used a sample volume of 1 mm, a wall filter of 50 to 100 Hz, a 5 degrees to 19 degrees insonation angle in the MCA and UA, and below 60 degrees in the SRA and IRA. Between the 22nd and 38th weeks of gestation, SV and DV increased in all fetal arteries (p<0.05), but SV decreased in the UA from 52.5 to 46.2 cm/s between the 34th and 38th gestational weeks (p<0.05). The RI was unchanged in the SRA and throughout most of the gestational weeks in the IRA (p>0.05), but decreased from 0.69 to 0.56 in the UA (p<0.05). In the MCA, it decreased from 0.85 to 0.75 between the 26th and 38th gestational weeks (p<0.05). In conclusion, the volume of blood flow in the fetal organs necessary for their development is related to increased SV and DV and to decreased RI. The Doppler velocimetry measurements for normal fetuses could be compared with those for fetuses in high-risk pregnancies.     

Vector Doppler imaging of a spinning disc ultrasound Doppler phantom

Vector Doppler methods are used to obtain angle independent in-plane velocity information. Velocity magnitude as well as direction are reconstructed from regular steered colour flow and from split-aperture Doppler acquisitions. Spatially resolved in-plane velocity was obtained through Doppler colour flow mode and subsequent data triangulation. A depth-invariant constant Doppler angle was achieved by using a depth expanding transmit-receive Doppler aperture. Velocities of up to 50 cm s(-1) and 360 degrees vector velocity directions were measured. This was achieved by creating a spinning solid disc phantom. Such a phantom was built to allow underwater mounting and spinning of a solid disc-shaped ultrasound phantom (maximum velocity of 50 cm s-1). Doppler triangulation was realised by steered Doppler and by a split-aperture approach. Results of both imaging methods are shown. Split-aperture results showed errors of less then 10% for velocity magnitude estimation and less then 2.5 degrees for directional information.     

In Vivo Lateral Blood Flow Velocity Measurement Using Speckle Size Estimation

In previous studies, we proposed blood measurement using speckle size estimation, which estimates the lateral component of blood flow within a single image frame based on the observation that the speckle pattern corresponding to blood reflectors (typically red blood cells) stretches (i.e., is “smeared”) if blood flow is in the same direction as the electronically controlled transducer line selection in a 2-D image. In this observational study, the clinical viability of ultrasound blood flow velocity measurement using speckle size estimation was investigated and compared with that of conventional spectral Doppler of carotid artery blood flow data collected from human patients in vivo. Ten patients (six male, four female) were recruited. Right carotid artery blood flow data were collected in an interleaved fashion (alternating Doppler and B-mode A-lines) with an Antares Ultrasound Imaging System and transferred to a PC via the Axius Ultrasound Research Interface. The scanning velocity was 77 cm/s, and a 4-s interval of flow data were collected from each subject to cover three to five complete cardiac cycles. Conventional spectral Doppler data were collected simultaneously to compare with estimates made by speckle size estimation. The results indicate that the peak systolic velocities measured with the two methods are comparable (within ±10%) if the scan velocity is greater than or equal to the flow velocity. When scan velocity is slower than peak systolic velocity, the speckle stretch method asymptotes to the scan velocity. Thus, the speckle stretch method is able to accurately measure pure lateral flow, which conventional Doppler cannot do. In addition, an initial comparison of the speckle size estimation and color Doppler methods with respect to computational complexity and data acquisition time indicated potential time savings in blood flow velocity estimation using speckle size estimation. Further studies are needed for calculation of the speckle stretch method across a field of view and combination with an appropriate axial flow estimator.     

Implementation of spectral width Doppler in pulsatile flow measurements

In this paper, we present an automatic beam-vector (Doppler) angle and flow velocity measurement method and implement it in pulsatile flow measurements using a clinical Doppler ultrasound system. In current clinical Doppler ultrasound flow velocity measurements, the axis of the blood vessel needs to be set manually on the B-scan image to enable the estimation of the beam-vector angle and the beam-vector angle corrected flow velocity (the actual flow velocity). In this study, an annular array transducer was used to generate a conical-shaped and symmetrically focused ultrasound beam to measure the flow velocity vectors parallel and perpendicular to the ultrasound beam axis. The beam-vector angle and flow velocity is calculated from the mode frequency (f(d)) and the maximum Doppler frequency (f(max)) of the Doppler spectrum. We develop a spectrum normalization algorithm to enable the Doppler spectrum averaging using the spectra obtained within a single cardiac cycle. The Doppler spectrum averaging process reduces the noise level in the Doppler spectrum and also enables the calculation of the beam-vector angle and flow velocity for pulsatile flows to be measured. We have verified the measurement method in vivo over a wide range of angles, from 52 degrees to 80 degrees, and the standard deviations of the measured beam-vector angles and flow velocities in the carotid artery are lower than 2.2 degrees and 12 cm/s (about 13.3%), respectively.     

Testing ultrasonic pulsed Doppler instruments with a physiologic string phantom

The spatial, temporal, and frequency resolution of conventional ultrasonic Doppler instruments and the time/space distortions in two-dimensional color Doppler imaging systems can be measured using a pulsatile moving string target. The diameter of the string is small compared with the Doppler sample volume, the velocity (speed and direction), acceleration and timing of the string motions are precisely known with reference to the R wave timing mark, and the spatial location of the string is known. A loop of surgical thread or monofilament fishline running between pulleys is driven by a motor that provides constant string speeds from 0.05 to 150 cm/s and variable string speeds programmed to mimic arterial velocity waveforms from the carotid, aortic, and femoral arteries. Constant string speeds are used to evaluate the Doppler sensitivity, frequency processing, and sample volume size; pulsatile movement of the string provides a physiologic model to evaluate the temporal performance of conventional Doppler systems and the temporal and spatial performance of two-dimensional color Doppler imaging scanners.     

Doppler spectrum analysis versus direct femoral artery pressure measurement for rapid assessment of aortoiliac obstruction.

Adequate patient selection is required to limit the clinical workload and improve the cost-effectiveness of noninvasive hemodynamic evaluation of the aortoiliac system. In a prospective blinded fashion the traditional invasive technique of direct femoral artery pressure measurements and the computerized Doppler spectrum analysis of blood flow velocities in the common femoral artery were studied. Both tests for rapid assessment of aortoiliac obstruction were compared with duplex ultrasonographic imaging, using a peak systolic velocity ratio of 2.5 to demonstrate stenoses of 50% or more. In a series of 17 consecutive patients (34 aortoiliac segments) with suspected aortoiliac obstructive disease, a good level of agreement (kappa = 0.6) was found for both methods when compared with duplex scanning. Analysis of deviations from the duplex registrations indicated an overestimation of the pathologic cases using femoral artery pressure measurements and an underestimation using Doppler spectrum analysis of blood flow velocities in the common femoral artery. Both methods were well tolerated, but femoral artery pressure measurements had a higher technical failure rate. Because of its noninvasive character and its feasibility the Doppler technique is preferred for the selection of patients for more extensive duplex sonographic investigation.     

Vector Doppler: accurate measurement of blood velocity in two dimensions.

An ultrasound Doppler system capable of determining both the magnitude and direction of complex blood velocities has been developed and demonstrated. This system uses a single transmitter and two receivers to resolve orthogonal velocity vector components. The system has been tested on a moving string phantom and on a carotid artery. The method may improve the detection of early vascular diseases and improve the accuracy of volumetric blood flow measurements in peripheral arteries.     

股动脉断裂显微外科修复24例分析

目的探讨股动脉断裂显微外科修复的治疗方法。方法2005年1月至2009年12月,对24例因股动脉断裂采用端端吻合、大隐静脉移植修复方法行急诊手术治疗。结果术后肢体均存活,患肢足背动脉搏动恢复,肤色、皮温及毛细血管反应正常。术后3个月行彩色多普勒检查,吻合口血管通畅,无血栓形成及吻合口狭窄,下肢行走功能恢复。结论急诊抢救休克以及尽早修复重建血管是治疗股动脉断裂的关键。     

高频超声评价自体骨髓间充质干细胞移植对免缺血肢体血管再生的影响

背景:研究发现干细胞可分化为血管内皮细胞,并可进一步分化形成新生毛细血管,自体骨髓间充质干细胞移植促进血管再生正是利用这一原理达到治疗下肢缺血的目的.目的:采用高频二维超声及彩色多普勒血流成像检测评价自体骨髓间充质干细胞移植后兔缺血肢体血管再生的情况.设计、时间及地点:随机对照动物实验,于2007-03/2008-04在无锡市第三人民医院完成.材料:新西兰大白兔24只,随机分为模型对照组、细胞移植组,12只/组.方法:2组兔均建立后肢缺血动物模型,造模1周后,细胞移植组取体外分离培养的Brdu标记的自体骨髓间充质干细胞,在腓肠肌部位皮下分多点注射,细胞悬液总体积0.5 mL,细胞总量2×105个;模型对照组于相同部位注射等量生理盐水.主要观察指标:对兔股动脉及股浅动脉起始段行高频二维超声及彩色多普勒血流成像检测,测量股动脉血管内径、血流峰值速度、血流加速时间;取缺血部位肌肉组织,免疫组织化学染色检测移植细胞分布情况及病理学检查血管再生情况.结果:移植后2周,高频超声检查细胞移植组兔股动脉内径、血流峰值速度均大于模型对照组,血流加速时间小于模型对照组(P<0.01).免疫组织化学染色后移植部位可见抗Brdu染色阳性细胞的存在,病理切片示细胞移植组血管密度明显高于模型对照组.结论:自体骨髓间充质干细胞移植具有促进血管生成的作用,有望成为一种简单有效的治疗下肢缺血的方法,同时高频超声检测股动脉为自体骨髓间充质干细胞移植效果评价提供了有效实用的方法.     

正常成人肾内动脉血流动力学的彩色多普勒研究

以彩色多普勒研究１７２例健康成人３４４只肾的肾内动脉（肾门部主肾动脉、段动脉、叶间动脉）血流收缩峰速度（ＳＶ）、阻力指数（ＲＩ）和加速度（ＡＣ），建立不同年龄组、不同分级血管各参数的正常值范围，旨在了解正常肾脏血流动力学变化并为超声评价各种肾脏病变提供对照依据。研究表明，随肾内动脉逐级分支，其ＳＶ、ＲＩ和ＡＣ值依次递减；ＳＶ与年龄呈负相关关系，ＲＩ与年龄呈密切正相关关系；６０岁以上ＲＩ值增高显著。     

Feasibility of Dual Doppler Velocity Measurements to Estimate Volume Pulsations of an Arterial Segment

If volume flow was measured at each end of an arterial segment with no branches, any instantaneous differences would indicate that volume was increasing or decreasing transiently within the segment. This concept could provide an alternative method to assess the mechanical properties or distensibility of an artery noninvasively using ultrasound. The goal of this study was to determine the feasibility of using Doppler measurements of pulsatile velocity (opposed to flow) at two sites to estimate the volume pulsations of the intervening arterial segment. To test the concept over a wide range of dimensions, we made simultaneous measurements of velocity in a short 5 mm segment of a mouse common carotid artery and in a longer 20 cm segment of a human brachial-radial artery using a two-channel 20 MHz pulsed Doppler and calculated the waveforms and magnitudes of the volume pulsations during the cardiac cycle. We also estimated pulse wave velocity from the velocity upstroke arrival times and measured artery wall motion using tissue Doppler methods for comparison of magnitudes and waveforms. Volume pulsations estimated from Doppler velocity measurements were 16% for the mouse carotid artery and 4% for the human brachial artery. These values are consistent with the measured pulse wave velocities of 4.2 m/s and 10 m/s, respectively, and with the mouse carotid diameter pulsation. In addition, the segmental volume waveforms resemble diameter and pressure waveforms as expected. We conclude that with proper application and further validation, dual Doppler velocity measurements can be used to estimate the magnitude and waveform of volume pulsations of an arterial segment and to provide an alternative noninvasive index of arterial mechanical properties. (E-mail: cjhartley@ieee.org)     

Femoral blood flow in term and premature infants

A specially designed 20-MHz pulsed Doppler velocity meter was used to quantify noninvasively common femoral artery blood flow and blood flow characteristics in 11 normal term and 12 premature infants. Femoral artery mean velocity (vf), blood flow (Q), weight-normalized blood flow (Q/kg) and pulsatility index (PI) were determined for the two groups. Mean values for Q (+/- SD) in the term and preterm infants were 27.3 +/- 10.3 and 23.4 +/- 14.7 (ml X min-1), respectively (P less than 0.1). Mean Q/kg for the premature infants was significantly higher (22.1 +/- 12.8) than that for the term infants (9.1 +/- 4.2), P less than 0.005. This study demonstrates differences between the pulsatile blood flow and velocity characteristics of the femoral arteries of premature and of full-term infants.     

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。     

彩色多普勒超声诊断外周血管动脉瘤与栓塞

采用彩色多普勒超声检查外周血管动脉瘤与栓塞，选择１０例手术证实的患者，其中５例做过血管造影。两维图像显示动脉瘤易伴血栓形成，本文６例动脉瘤中１例右颈内动脉瘤因血栓充填血管造影误诊为软组织肿瘤，彩色多普勒发现瘤内彩色血来包绕血凝块旋转。５／６例外伤性及感染性假性动脉瘤可直接显示破裂的血管血流喷向肿块内，与手术发现完全一致．脉冲频谱呈动脉高速血流、双相。１例骼动脉及１例股动脉栓塞显示血管暗区消失，管壁模糊，血管内彩色血流，脉冲多普勒信号减弱及消失。２例蔓状血管瘤表现边界不清，多条迂曲管状的无回声暗区连成一片，形成蜂窝团样，彩色多普勒显示暗区均被血流充填。作者认为该检查方法诊断周围血管动脉病变能得到可靠和有价值的信息。     

Assessment of blood flow velocity waveforms of the pulmonary circulation by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography.

OBJECTIVE: To assess (1) pulmonary artery and peripheral pulmonary blood flow by using a multigate spectral Doppler system and standard pulsed color Doppler ultrasonography and (2) the reproducibility of peripheral pulmonary artery blood flow velocity waveforms. METHODS: Thirty-three women were enrolled in the study Fetal pulmonary artery flow velocity waveforms were investigated by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography plus color flow mapping. To establish the relationship between these 2 methods, we calculated the correlation coefficient, coefficient of variation, and limits of agreement. RESULTS: The 2 methods were not significantly correlated. The range of measurement agreement for these 2 methods suggests that there is a significant difference between the main and peripheral pulmonary artery blood flow, and the difference should be taken into account in the interpretation of Doppler flow velocity studies of the pulmonary artery. CONCLUSIONS: Multigate spectral Doppler scanning with power Doppler imaging may be a better way to assess the average flow impedance in a highly vascularized organ. This technique supplies a large number of Doppler signals in the region of interest and offers a quantified range of Doppler measurements, improving our understanding of fetal hemodynamics.     

Duplex ultrasonographic assessment of gut blood flow velocity: effect of meal composition in normal full-term newborns after first feed.

We used transcutaneous duplex Doppler ultrasound to measure superior mesenteric artery and celiac artery blood flow velocity in 45 normal healthy newborn infants. Doppler indices of PSV, TAMV, EDV, and PI were measured immediately before and after feeding at 15 minute intervals up to 75 minutes. Maximal changes were compared with preprandial baseline values. There were no significant differences between the preprandial and postprandial blood pressures and heart rates. In the superior mesenteric artery the PSV, TAMV, and EDV rose progressively and peaked 30 minutes after feeding in both the milk-fed group and the 5% glucose, water-fed group over baseline (73 versus 41% and 110 versus 63%, 130 versus 100%) (P < 0.05). The PI decreased significantly in the milk-fed group only. There were no significant changes in any blood flow velocity parameters derived from the celiac artery. We conclude that duplex ultrasonography provides a noninvasive means of studying the reactivity of the splanchnic arterial circulation to different stimuli. The chemical composition of the meal is a significant factor determining postprandial mesenteric hyperemia.     

Effects of isosorbide dinitrate on the pattern of arterial blood flow in healthy human subjects

1. Blood velocity measurements have been made in the superficial femoral artery, 10 cm downstream of the common femoral artery bifurcation, in healthy human subjects, using a multi-channel Doppler ultrasound device. 2. In a randomized double-blind protocol, the effects of isosorbide dinitrate were examined during a 2 h period. 3. The changes induced by isosorbide dinitrate include: (i) an increase in the width of the artery and a reduction in brachial arterial blood pressure, implying relaxation of arterial smooth muscle; (ii) an increase in reverse flow and a decrease in time-averaged mean velocity associated with a relatively small decrease of the velocity excursion during the cardiac cycle, implying an increase in flow pulsatility; and (iii) an alteration of the flow pattern both in the core and near the vessel walls.