Assessment of Doppler velocimetry of the fetal umbilical artery by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography plus color flow mapping.

The Doppler signal of blood flow originates from the sonographic scattering from the circulating red blood cells. However, the physics of blood flow is complex as expressed by the Bernoulli equation, and the flow velocity at different positions in the laminar flow of the same vessel is variable. Using multigate spectral Doppler scanning, we recorded multiple Doppler flow signals over a segment of the umbilical artery and compared the results with traditional pulsed Doppler ultrasonography. The intraobserver variations of the pulsatility index, the resistive index, and the systolic-to-diastolic ratio were evaluated in 30 human fetuses between 29 and 42 weeks of gestation. The correlation coefficient was calculated to establish the relationship between the results of multigate spectral Doppler scanning and the traditional pulsed Doppler ultrasonographic method. The Doppler indices of these two measurements are all significantly correlated. However, since a significant difference exists between the Doppler flow measurements of multigate spectral Doppler scanning and the traditional pulsed Doppler ultrasonographic method, the range of measurement agreement for these two methods suggests that this difference should be taken into account in the interpretation of Doppler flow velocity measurements.     

Recording of blood flow velocity waveforms in the uteroplacental and umbilical circulation: reproducibility study and comparison of pulsed and continuous wave Doppler ultrasonography

Reproducibility of the blood flow velocity waveforms (FVW) recorded from the umbilical artery and the arcuate arteries on the right and left side of the placenta was examined in 8 women with normal pregnancies and anterior placentas. The FVW were recorded using a 2-MHz pulsed Doppler ultrasound system in combination with a real-time linear-array scanner. The FVW were characterized by the pulsatility index (PI) and systolic/diastolic (S/D) ratio. For the PI, the mean coefficients of variation between six operator pairs in the umbilical artery and the left and right arcuate arteries were 8.4%, 26%, and 21.5%, respectively. These findings suggest that, in clinical practice, the umbilical artery FVW is reproducible, but the usefulness of arcuate artery FVW is limited by the wide variation of Doppler signals. Paired recordings of FVW were obtained from the umbilical, arcuate, and uterine arteries using pulsed wave and continuous wave Doppler ultrasonography in a randomized order in another 21 pregnant women with anterior placentas. There was no difference between the two Doppler modes for any of the measured waveform indices.     

Doppler blood velocity waveforms in the umbilical artery as an indicator of fetal well-being

Doppler blood velocity waveforms were analyzed from the umbilical artery as an indication of fetal well-being. Since the ratio of systolic to diastolic peak flows (A/B) reflects placental vascular resistance, an abnormality of this value may accurately predict compromised fetuses. Twenty-one studies were performed on 13 patients, using a new duplex system for real-time imaging and range-gated pulsed Doppler analysis, and compared to normal standards. Thirteen studies done in nine uneventful pregnancies were consistently normal. However, abnormal studies were found in the four patients reported as case histories, including women with sickle cell anemia, systemic lupus, diabetes, and growth retardation. The A/B ratio was felt to have predicted potential fetal compromise, including the two fetal deaths. Therefore, with certain cautions, we feel that this rapid, non-invasive technique is useful as a serially applicable reflector of the status of fetoplacental circulation.     

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     

Prediction of brain blood flow using pulsed Doppler ultrasonography in newborn lambs

The purpose of this study was to evaluate the ability of pulsed Doppler ultrasonography to predict brain blood flow by comparing measurements made in basal cerebral arteries using a pulsed Doppler system with measurements of brain blood flow using radioactive microspheres in lambs. We measured the instantaneous maximum velocity during peak systole and end diastole and the mean velocity over the pulse cycle in basal cerebral arteries, calculated Pourcelot's index of resistance and Gosling's pulsatility index, and used regression analysis to compare the pulsed Doppler measurements with brain blood flow measured with radioactive microspheres. Pulsed Doppler measurements of the peak systolic, end diastolic, and mean flow velocity in basal cerebral arteries were directly related to brain blood flow. In contrast, no linear relationship was detected between the resistance or pulsatility indices and brain blood flow measured by microspheres (p greater than 0.14). Prediction of brain blood flow for individual subjects lacks the quantitative precision necessary for use as a clinical tool. However, the direct relationship between brain blood flow and the peak systolic, end diastolic, and mean flow velocities in basal cerebral arteries supports the use of these measurements in clinical research for the qualitative assessment of change in brain blood flow.     

彩色多普勒超声观察不同孕周正常胎儿动脉血流的价值

目的：探讨不同孕周胎儿肾动脉（RA）、脐动脉（UA）、大脑中动脉（MCA）血流参数的变化情况,确定正常胎儿RA、UA、MCA血流参考值,并分析RA、UA、MCA血流参数与孕龄的关系。方法选取2013年1～12月在该院行产前检查的185例孕周为4～41周的正常单胎孕妇为研究对象,采用彩色多普勒超声测量胎儿 RA、UA、MCA的阻力指数（RI）、搏动指数（PI）、收缩期峰值流速（PS）及收缩期峰值流速与舒张末期流速比值（S/D）。结果随着孕周的增加,胎儿RA、UA、MCA中PS值显著增加,而RA、UA中RI、PI、S/D值显著减少。经相关性分析可知,RA、UA、MCA中RI、PI、S/D与孕周呈负相关性（P＜0．05）,而RA、UA、MCA中PS与孕周呈正相关性（P＜0．05）。结论应用彩色多普勒测量不同孕周胎儿RA、UA、MCA血流动力学参数能有效了解胎儿颅脑循环、胎盘循环及全身血流循环状态。通过建立正常胎儿血流参数参考范围可为超声预测胎儿宫内生长情况提供参考依据。     

Comparison of blood velocity waveform indices recorded by pulsed Doppler and continuous wave Doppler in the umbilical artery

A comparison was made between the AB ratio, resistance index (RI), and pulsatility index (PI), calculated from tracings obtained by pulsed Doppler (PD) and continuous wave (CW) Doppler devices in 14 uncomplicated singleton pregnancies. The AB ratio, RI, and PI were a slightly higher for the CW Doppler compared to the PD system, although not significantly (p = 0.18, p = 0.21, and p = 0.44, respectively). The difference in signal to noise ratio (S/N ratio) between the PD and CW Doppler systems was felt to be the reason for the discrepancy in the calculated velocity waveform indices.     

Ductus venosus blood flow velocity waveforms in the human fetus--a Doppler study.

Successful human fetal ductus venosus flow velocity waveform recording was achieved cross sectionally in 48 out of 60 women at 19-22, 27-30 and 36-39 weeks of gestation. The ductus venosus shows a pulsatile flow pattern consisting of a systolic and diastolic forward component without a late diastolic reverse component as demonstrated in the inferior vena cava. Peak systolic velocities as high as 40-80 cm/s were observed. A statistically significant increase in time-averaged velocity, peak systolic and peak diastolic velocity with advancing gestational age was established.     

彩色多普勒对颈内动脉狭窄患者视网膜中央动脉的血流检测

目的了解不同程度的颈内动脉狭窄患者,其视网膜中央动脉的血流状况,探讨颈内动脉狭窄与视网膜中央动脉血流的病变关系。方法选颈内动脉彩色多普勒超声检查,诊断有明确颈内动脉粥样硬化造成颈内动脉狭窄的患者54例,其中轻度狭窄28例(直径狭窄率<50%),中度及中度以上狭窄26例(直径狭窄率≥50%)。对照组40例,为彩色多普勒证实无颈内动脉粥样硬化患者。测量入组患者视网膜中央动脉及眼动脉的各项血流参数,包括收缩期峰值流速(Vs)、舒张末期流速(Vd)以及血管阻力指数(RI)。结果随着颈内动脉狭窄程度的加重,视网膜中央动脉的血流动力学参数会发生相应变化,其中颈内动脉中重度狭窄组的视网膜中央动脉参数改变最明显。而眼动脉各参数与对照组相比无显著统计学差异。结论颈内动脉狭窄可影响视网膜中央动脉供血,彩色多普勒超声检查可明确颈内动脉及眼部供血情况。     

Alterations in segmentary branch pulmonary artery blood flow velocimetry in fetuses of diabetic mothers.

OBJECTIVE: To evaluate pulmonary blood flow in fetuses of diabetic mothers by measuring changes in fetal segmentary pulmonary artery blood flow velocimetry throughout pregnancy. METHODS: Thirty-eight women with pregestational diabetes between weeks 18 and 38 were compared with 99 women with singleton low-risk gestations as controls. Flow velocity waveforms at the proximal middle and distal segments of the right pulmonary artery were obtained with power and color Doppler sonography in all fetuses. The pulsatility index of each segment was compared between the 2 groups. The mean value and 95% confidence interval for each segment were determined in correlation with gestational age for both groups. RESULTS: The highest mean pulsatility indices were obtained in the proximal segment of the pulmonary artery and were 2.25 in the diabetes group and 2.36 in controls. The mean pulsatility indices were significantly decreased in the middle and distal segments to 1.59 and 1.10 in the diabetes group and to 1.57 and 1.02 in controls (P < .05). There were no significant differences in pulsatility indices measured at the proximal and middle segments between the study and control groups. However, the mean pulsatility index +/- SD measured at the distal segment in the diabetic group was 9% higher than in controls (1.10 +/- 0.13 versus 1.02 +/- 0.12; P = .01). The mean pulsatility index (in the study and control groups) in each arterial segment did not change significantly throughout gestation (P > .1). CONCLUSIONS:. In human fetuses throughout gestation, the pulmonary circulation maintains stable vascular resistance in both diabetic and normal pregnancies. However, in all gestations, the pulsatility index in each segment of the pulmonary artery is unique and reflects the proximity to the heart and the impedance at each location. The significantly higher pulsatility index in the diabetes group might be related to alterations in the microcirculation of diabetic patients.     

Detection of renal artery stenosis: experimental and clinical analysis of velocity waveforms

Mass screening of hypertensive patients by a noninvasive method could uncover the 10% of those cases where renal artery stenosis is the primary etiology. Treatment by transluminal angioplasty or surgery could replace a long-term medical regimen. To investigate an ultrasonic technique, normal velocity waveforms were obtained from the abdominal aorta, celiac artery and renal arteries in seven mongrel dogs using a 5 MHz, continuous-wave Doppler detector. Renal artery pressure gradients, volume flow rates and velocity recordings were subsequently made during induced proximal renal artery stenoses. The ratio of peak renal artery frequency to peak aortic frequency was 88% sensitive to stenoses of greater than 20 mm Hg pressure gradient, while the renal artery systolic frequency window was 79% sensitive to the same obstructions. Ninety-five hypertensive and vascular surgical patients were examined using a 3 MHz duplex scanner with 175 of the 190 (92%) renal arteries adequately detected (clear signal with high diastolic component). Analysis of velocity waveforms based on peak frequency, proximal to distal peak frequency changes, evidence of flow disturbances and associated bruit were compared to contrast arteriograms in 84 vessels. Of the 76 (90%) arteries adequately examined by duplex scanning, 59 of 61 (97%) with 0-59% diameter reduction, 10 of 12 (83%) with 60-99% diameter reduction and 1 of 3 (33%) occlusions were correctly identified. Velocity waveform analysis can accurately detect renal artery stenosis and may prove effective in mass screening of hypertensive patients for renovascular disease.     

冠状动脉血流储备的经胸多普勒超声心动图与冠状动脉内多普勒血流测量的对照研究

目的　①探讨经胸声学造影二次谐波多普勒超声心动图 (TTDE)探测冠状动脉左前降支(LAD)远端血流的可行性 ;②与冠状动脉内多普勒 (ICD)相对照 ,分析研究LAD冠状动脉血流储备(CFR)。方法　利用TTDE连续检测 110例患者LAD血流。冠状动脉血流速度储备 (CFVR)为注射腺苷后的最大平均血流速度与静息状态平均血流速度的比值。结果　CFVR探测的成功率为 96%。TTDE所探测的CFVR(2 .83± 0 .68)与ICD所探测的结果 (2 .91± 0 .74)密切相关 (r =0 .83 ,Y =0 .76X + 0 .61,P <0 .0 0 1)。结论　TTDE结合声学造影及二次谐波技术是一项可行、可信的无创性探测CFVR的方法 ,可用于冠状动脉病变的探测及冠脉介入治疗的随访。     

彩色多普勒超声检测妊高征血流速度比值的临床意义

目的：通过对妊高征（PIH）胎儿脐动脉（UmA)，大脑中动脉（McA)及孕妇子宫动脉（UtA)速度比值的检测，探讨其在预测围产儿结局中的价值。材料与方法：应用彩色多普勒超声测定48例妊高下及60例正常中晚期妊娠胎儿UmA,McA及孕妇UtA的S／D值，分析正常妊娠与不同程度妊高征S／D值的变化以及S／D值与围产儿结局的关系。结果；妊高征时胎儿Uma,McA及孕妇UtA的S／D值有不同程度变化，尤以重度妊高征S／D值变化最明显，表现为胎儿UmA,UtA的S／D升高，McA的／SD值降低，UmA S/D值改变敏感于UtA,McA；而McA的S／D值对围产儿结局有更好的预报的S／D值升高；McA的S／D值降低；UmA S/D改变敏感于UtA,McA，而McA的S／D值对围产儿结局有更好的预报价值。结论：本研究为脐动脉，大脑中动脉及子宫动脉速率比值监护妊高征胎儿宫内状况，预测围产儿结局提供理论依据。     

Middle cerebral artery peak systolic and ductus venosus velocity waveforms in the hydropic fetus.

OBJECTIVE: The purpose of this study was to assess whether Doppler assessment of the middle cerebral artery (MCA) peak systolic velocity (PSV) and ductus venosus (DV) velocity waveforms during sonography of hydropic fetuses may specify the cause of fetal hydrops. METHODS: A level II sonographic examination was performed in 16 hydropic fetuses, and the MCA PSV and DV velocity waveforms were assessed. The MCA PSV values divided hydropic fetuses into anemic (group 1) and nonanemic (group 2) fetuses. In group 2 fetuses, the DV was defined as normal or abnormal. Sonographic examination and Doppler assessment of these vessels specified the cause of hydrops and indicated the use of specific investigations for diagnosing the etiology of fetal hydrops. RESULTS: Seven of 16 fetuses had MCA PSV values greater than 1.50 multiples of the median (group 1). Nine of 16 fetuses had normal MCA PSV values (group 2); among them, 7 of 9 had either absent or reversed flow in the DV, and 2 had a normal DV. In group 1, the cause of fetal anemia was investigated by maternal serum tests, and 5 cordocentesis procedures were performed. In group 2, 7 of 9 fetuses had reversed flow in the DV, which suggested a cardiac abnormality confirmed by echocardiography. Five cordocentesis procedures were performed for fetal karyotype, and in 2 fetuses, the cause of hydrops was idiopathic. CONCLUSIONS: Our data suggest that assessment of the MCA PSV and DV velocity waveforms in the hydropic fetus may further our knowledge of the etiology of hydrops and may indicate which investigations among the many available should be used for diagnosing the cause of fetal hydrops.     

正常冠脉的腔内多普勒血流速度描记

目的： 研究正常冠脉腔内多普勒血流频谱特征。方法： 我们用多普勒血流速度描记钢丝对７ 例行选择性冠脉造影正常并且无微循环病变基础者进行冠脉内多普勒血流速度测定。其中男６ 例, 女１ 例。年龄４９±６－５７ 岁（３７～５８ 岁）。左前降支（ＬＡＤ）６ 支; 左回旋支（ＬＣＸ）４ 支和右冠状动脉（ＲＣＡ）７ 支。结果： ①正常人冠脉近端ＡＰＶ略高于远端, 但差别无显著意义（Ｐ＞０－０５）。②同一冠脉近端流速高于远端, 二者的流速之比（ｐ／ｄＶＲ）＜ １－７。③三支冠脉近端和远端血流频谱均呈舒张期优势型, ＤＳＶＲ＞１, 这种特征在左冠脉较明显。④同一冠脉近端ＤＳＶＲ则与远端相似, 无显著差异（Ｐ＞ ０－０５）。⑤充血反应时ＤＳＶＲ仍＞ １, 说明冠脉血流仍保持舒张期优势的特征。⑥ＬＡＤ, ＬＣＸ和ＲＣＡ的ＣＦＲ均＞ ３, 差别无显著意义（Ｐ＞０－０５）。结论： 冠脉近端和远端的血流频谱均呈舒张期优势型, 并且在充血反应时仍保持舒张期优势的特征。ＬＡＤ, ＬＣＸ和ＲＣＡ的ＣＦＲ均＞ ３, 三支冠脉间测值的差别无显著意义。     

Doppler waveforms in the renal arteries of normal children

Blood velocity waveforms in peripheral arteries vary such that decreasing vascular resistance results in a relative increase in diastolic velocity at steady state. We measured blood velocity in renal arteries of 20 children (age: 119 months ± 37 months; weight: 38 kg ± 15 kg) to establish normal values, and to explore the relationship between these waveforms and central hemodynamics. Using image-directed pulsed Doppler echocardiography, M-mode measurements and cardiac index were recorded. Renal hila were visualized via the flank for Doppler sampling. Peak systolic velocity (A) and minimal diastolic velocity (B) were determined. The results (mean ± SD) were as follows: Renal artery A/B = 2.9 ± 0.74 (range 1.9 to 5.1). Characteristic waveforms were identical bilaterally and had continuous diastolic foward flow: A/B was independent of central hemodynamics within the resting normal range, varying inversely with age and size.     

Doppler assessment of renal blood flow velocity waveforms in the anemic fetus before and after intravascular transfusion for severe red cell alloimmunization.

Image-directed pulsed Doppler ultrasonography demonstrated a decrease in the pulsatility index of the renal artery in 9 anemic fetuses (less than 30 weeks, menstrual age) soon after intravascular transfusion. The pulsatility index returned to pretransfusion values the day following the transfusion. End diastolic blood velocity in the renal artery could not be measured before the transfusion, was detectable immediately after the procedure, and was again nonmeasurable one day after the transfusion. These data suggest an increase in renal blood flow in the anemic fetus soon after intravascular transfusion to eliminate excess fluid.     

Diagnosis of portal vein tumor thrombus by pulsed Doppler ultrasonography.

The blood flow of portal vein thrombus was studied by pulsed Doppler ultrasonography in 21 patients with tumor thrombus and 14 with blood clot thrombus. Pulsatile waves were observed in 19 of the 21 with tumor thrombus, with backward continuous waves in 3, and forward/backward continuous waves in 2. In contrast, forward continuous waves were observed in 2 of the 14 with blood clot thrombus. By color imaging, the blood flow could be observed in 9 of 14 with tumor thrombus, but in 1 of 7 with blood clot thrombus. Pulsatile and backward continuous waves were characteristic of tumor thrombus.