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At least 19 recordsLinked to original sources

PubMedDate not supplied

[Ultrasound Doppler sonography in obstetrics. A comparison between simple Doppler methods (continuous or pulsed Doppler) and the duplex system (combination of B-image and pulse Doppler)].

120 pregnant women between the 26th and 42nd week of gestation have been examined using simple Doppler-units with pulsed- or continuous-wave technique and duplex Doppler-units (combined B-mode and pulsed-wave Doppler). The umbilical and uterine arteries were measured with both units in a semi-recumbent position at the same time by the same examiner. Only ideal flow profiles were taken to calculate the S/D-ratio. Our results were correlated to the fetal outcome, to all cases of pre-eclampsia and to all cases of intra-uterine growth retardation. Except in one of these cases we got the majority of pathological results using simple Doppler-units. Only in pre-eclampsia the duplex Doppler-units had the majority of pathological results. Even in normal fetal outcome the majority of simple Doppler-unit results are pathological. This finding is due to the impossibility to localize the vessel exactly using simple Doppler-units. Sensitivity is higher in simple Doppler-techniques (74.3% to 52.9%), specificity is higher in duplex Doppler-technique (77.9% to 52.6%).

Female↗

PubMed2003

Doppler angle and flow velocity mapping by combined Doppler shift and Doppler bandwidth measurements in optical Doppler tomography.

Accurate estimation of flow velocity requires measurement of Doppler angle, which is not available in general clinical applications. We describe a novel method of direct Doppler angle and flow velocity mapping that uses a conventional single-beam optical Doppler tomography system. The Doppler angle is estimated by combination of Doppler shift and Doppler bandwidth measurements, and flow velocity is calculated from the Doppler shift and the estimated Doppler angle. In vivo study of lip microvascularization demonstrates that this method is capable of providing both flow speed and flow direction information.

Blood Flow Velocity↗

PubMed2003

Quantifying Doppler angle and mapping flow velocity by a combination of Doppler-shift and Doppler-bandwidth measurements in optical Doppler tomography.

Recently we introduced a novel procedure that estimates Doppler angle and flow velocity simultaneously by combining Doppler-shift and Doppler-bandwidth measurements with a conventional single-beam optical Doppler tomography device. Here we validate this method experimentally with two Intralipid flow setups that correspond to fixed Doppler angle and fixed flow speed. One set of data has a fixed flow speed of 53.6 mm/s with a Doppler angle that changes from 56 degrees to 90 degrees; the other has a fixed Doppler angle of 80 degrees with flow speed that changes from 18.5 to 141.9 mm/s. As obtained with the method introduced here, the Doppler-angle estimation accuracies of the two sets are 97.6% and 98.2%, respectively, and the estimation accuracies of flow speeds of the two sets are 94.3% and 90.4%, respectively.

Algorithms↗

PubMed1988

[Doppler effect in cardiology. Continuous Doppler, pulsed Doppler, Doppler color].

Echocardiography has contributed to the exploration of the heart by providing much information, and it has even given rise to new semiological concepts. However, abnormalities of intracardial blood flow, notably shunts and regurgitations, could only be diagnosed indirectly from their effects on cardiac cavities. A new step forward was the advent of pulsed and continuous doppler ultrasound, since from that moment it has been possible to demonstrate abnormal blood flows, to measure their velocity and to determine, albeit with some reservation, such crucial values as pressure gradients. Yet even when these two techniques were combined in the doppler-echotomography systems blind areas persisted, and a blood flow of strongly abnormal direction could in fact escape doppler velocimetry. This is where another development came to the rescue, for it enabled both normal and abnormal flows to be visualized in colours. Owing to this visualization, and provided all possible projections are used, it has become exceptional to "miss" an abnormal blood flow. The diagnosis is now easier and more accurate, and in a second stage the flow can be quantified by pulsed or continuous doppler ultrasound. The colour-coded doppler technique therefore has not superseded the previous one: one may say that it has merely increased diagnostic reliability, but is this not a decisive improvement?

Cardiology↗

PubMed2006

Color tissue Doppler myocardial velocities consistently underestimate spectral tissue Doppler velocities: impact on calculation peak transmitral pulsed Doppler velocity/early diastolic tissue Doppler velocity (E/Ea).

BACKGROUND: Color tissue Doppler (TD) measures mean myocardial velocities, whereas spectral TD measures peak velocities. Given that most data on left ventricular (LV) diastolic function used spectral TD, we investigated whether the differences in myocardial velocities between these modalities resulted in discrepancies in calculated E/Ea. METHODS: Patients were imaged using an ultrasound machine. The systolic (Sa), early diastolic (Ea), and late diastolic (Aa) myocardial velocities by color and spectral TD were measured at basal and midsegments of the LV septal, lateral, inferior, and anterior walls in the apical views. The average of basal septal and lateral Ea was combined with the early transmitral diastolic velocity (E) to obtain E/Ea. RESULTS: In all, 31 patients were imaged, with a mean LV ejection fraction of 47.7% +/- 19.9. There were significant correlations between Sa, Ea, and Aa by color and spectral TD at all sites (R = 0.92, P < .001 for Ea at basal lateral wall) and between spectral and color E/Ea (R = 0.85, P < .001). Sa, Ea, and Aa were significantly lower by color TD than by spectral TD (basal septal color Ea = 3.0 +/- 2.0 cm/s vs 5.6 +/- 2.5 cm/s for spectral Ea, P < .001). Consequently, E/Ea by color TD was significantly higher than by spectral TD (22.3 +/- 15.3 vs 13.6 +/- 7.8, P < .001). CONCLUSIONS: Although significant correlations exist, myocardial velocities measured using color TD significantly underestimate velocities by spectral TD. Consequently, E/Ea by color TD significantly overestimates E/Ea using spectral TD, which could lead to errors in assessment of LV diastolic function.

Artifacts↗

PubMed1999

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.

Female↗

PubMed2000

Clinical utility of Doppler echocardiography and tissue Doppler imaging in the estimation of left ventricular filling pressures: A comparative simultaneous Doppler-catheterization study.

BACKGROUND: Noninvasive assessment of diastolic filling by Doppler echocardiography provides important information about left ventricular (LV) status in selected subsets of patients. This study was designed to assess whether mitral annular velocities as assessed by tissue Doppler imaging are associated with invasive measures of diastolic LV performance and whether additional information is gained over traditional Doppler variables. METHODS AND RESULTS: One hundred consecutive patients referred for cardiac catheterization underwent simultaneous Doppler interrogation. Invasive measurements of LV pressures were obtained with micromanometer-tipped catheters, and the mean LV diastolic pressure (M-LVDP) was used as a surrogate for mean left atrial pressure. Doppler signals from the mitral inflow, pulmonary venous inflow, and TDI of the mitral annulus were obtained. Isolated parameters of transmitral flow correlated with M-LVDP only when ejection fraction <50%. The ratio of mitral velocity to early diastolic velocity of the mitral annulus (E/E') showed a better correlation with M-LVDP than did other Doppler variables for all levels of systolic function. E/E' <8 accurately predicted normal M-LVDP, and E/E' >15 identified increased M-LVDP. Wide variability was present in those with E/E' of 8 to 15. A subset of those patients with E/E' 8 to 15 could be further defined by use of other Doppler data. CONCLUSIONS: The combination of tissue Doppler imaging of the mitral annulus and mitral inflow velocity curves provides better estimates of LV filling pressures than other methods (pulmonary vein, preload reduction). However, accurate prediction of filling pressures for an individual patient requires a stepwise approach incorporating all available data.

Aged↗

PubMed1999

[Diagnosis of thyroid nodules by Doppler ultrasonography: a comparison between color Doppler and power Doppler ultrasonography].

The purpose of this study was to assess the usefulness of color and power Doppler imaging in thyroid nodules. The following 4 items were compared between malignant thyroid nodules (34 cases) and benign nodules (51 cases): 1) vascularity; 2) distribution of tumor vessels (none, marginal, peripheral, central); 3) nature of tumor vessels (tortuosity, interruption); and 4) FFT analysis. The distribution of tumor vessels on color Doppler images, nature of tumor vessels on power Doppler images, and the indices of PI, RI, and ATI in FFT analysis were useful in making the differential diagnosis between malignant and benign nodules. In terms of vascularity, including the distribution of tumor vessels on power Doppler images and nature of tumor vessels on color Doppler images, no statistically significant differences were found between malignant and benign nodules. Power Doppler images depicted tumor vessels in more detail than color Doppler images and were considered to extend the application of FFT analysis.

Diagnosis, Differential↗

PubMed2004

Evaluation of cervical lymph node vascularity: a comparison of colour Doppler, power Doppler and 3-D power Doppler sonography.

This study was undertaken to compare the performance of colour Doppler (CDS), power Doppler (PDS) and 3-D power Doppler sonography (3-D PDS) in the assessment of vascular pattern and vessel displacement of cervical lymph nodes. Colour Doppler (2-D CDS), power Doppler (2-D PDS) and 3-D power Doppler sonograms (3D PDS) of 145 cervical nodes were reviewed (metastases n=60, lymphoma n=30, tuberculosis n=23, reactive n=25, Kimura disease n=7). Sonograms of the three imaging modes were reviewed separately with an interval of 2 weeks. Lymph nodes were assessed for the vascular pattern (hilar, peripheral or mixed) and the presence or absence of displacement of hilar vascularity. For the assessment of displacement of hilar vascularity, only lymph nodes that showed hilar or mixed vascularity in the three imaging modes were included in the analysis. Results showed that there was a high level of agreement between CDS and PDS in assessment of vascular patterns (kappa=0.914), whereas the level of agreement between CDS and 3-D PDS (kappa=0.484) and between PDS and 3-D PDS (kappa=0.452) was low. There was a high level of agreement in the assessment of displacement of hilar vascularity among the three imaging modes (CDS and PDS, kappa=0.942; CDS and 3-D PDS, kappa=0.808; PDS and 3-D PDS, kappa=0.865). In the assessment of vascular patterns of cervical lymphadenopathy, CDS and PDS have a similar performance. However, accurate assessment of the vascular pattern of cervical nodes may be difficult using 3-D PDS. In the assessment of displacement of hilar vascularity, the performances of CDS, PDS and 3-D PDS are similar.

Adolescent↗

PubMed1992

[Doppler ultrasound study of breast tumors using color Doppler ultrasound, duplex ultrasound and the CW Doppler ultrasound].

The preoperative examinations by doppler-sonography of 83 patients with tumors of the breast are presented. The examinations are done with newest technique: duplex-sonography in slow-flow-technique (AI 3200, Dornier); colour-sonography in MEM-technique (AI 5200, Dornier) and synchronical colour-doppler++ (Quantum 2000, Siemens) and CW-doppler-sonography (Vasocope 3, Kranzbühler). There is a markable difference between the side of carcinoma and the normal side as well as pre- and postmenopausal patients. No difference is shown in cases of benign tumors and the normal side. The increasing blood flow of a malignant tumor is showed in changing the doppler parameters (A/B-ratio and resistance-index) and in the doppler wave form. The number of vessels found in or around a tumor is not a good criteria to find malignant diseases, the best criteria is the difference between sides of the mamma.

Blood Flow Velocity↗

PubMed2005

Evaluation of joint effusion in rabbits by color Doppler, power Doppler, and contrast-enhanced power Doppler ultrasonography.

PURPOSE: The aim of this prospective study was to evaluate the diagnostic value of power Doppler ultrasonography (PDUS) and contrast-enhanced PDUS (CEPDUS) in the depiction and characterization of experimentally induced arthritis in the rabbit. MATERIALS AND METHODS: Thirty rabbits were divided into three groups consisting of one control group (saline injection group) and two experimental groups: a suppurative arthritis group and a chemically induced synovitis group. The same amount (1 ml) of each agent was directly injected into the right hip joint. Serial color Doppler ultrasound (CDUS), PDUS, and CEPDUS images were obtained before and after injection. RESULTS: We observed that all of the infected knees in the suppurative arthritis group with Staphylococcus aureus demonstrated an increased signal on PDUS after inoculation. A minimal power Doppler signal was presented in the chemically induced synovitis group with talc injection, but none of the control knees demonstrated any increased signals. CEPDUS was the most sensitive imaging modality for evaluating the increase of blood flows in suppurative arthritis and was subsequently followed by PDUS and CDUS. CONCLUSION: The increased signals obtained with PDUS represent increased local blood flows; therefore, this technique can be used for evaluating the degree of inflammation. Furthermore, using the contrast agent enhances the sensitivity of PDUS, and it can even be useful for differentiating borderline cases.

Animals↗

PubMed2002

Comparison of Doppler echocardiography, color M-mode Doppler, and Doppler tissue imaging for the estimation of pulmonary capillary wedge pressure.

To overcome the limitations of mitral inflow parameters for predicting pulmonary capillary wedge pressure (PCWP), combined indices (with Doppler tissue imaging or color M-mode Doppler) have been developed. This study was aimed to compare the accuracy of these indices to predict PCWP. Sixty-one patients were studied. The best correlations with PCWP were found for indices that combined isovolumic relaxation time with flow propagation velocity (color M-mode) or early diastolic velocity of the lateral mitral annulus (Doppler tissue). Both closely tracked changes in PCWP. The color M-mode-derived index was the most accurate in patients with normal systolic function.

Aged↗

PubMed1998

Comparison of regional myocardial velocities assessed by quantitative 2-dimensional and M-mode color Doppler tissue imaging: influence of the signal-to-noise ratio of color Doppler myocardial images on velocity estimators of the Doppler tissue imaging system.

M-mode color Doppler imaging of the myocardium affords a greater sampling rate and signal-to-noise (S/N) ratio than 2-dimensional (2D) imaging. In this study, we compared myocardial velocities assessed by 2D and M-mode Doppler tissue imaging (DTI) at the same site and evaluated the influence of the S/N ratio on velocity estimates of the currently used DTI systems. In patients with and without impaired regional left ventricular function, myocardial velocities assessed by 2D DTI were lower than those obtained with M-mode DTI. The difference between regional velocities derived from both imaging techniques was positively correlated with the extent of the "black zone," which could be considered as indirectly reflecting the S/N ratio for each frame. Thus in the clinical setting and on currently used echocardiographs, 2D DTI may provide underestimated regional myocardial velocities when compared with M-mode, mainly because of the influence of the lower sampling rate and S/N ratio on velocity estimators of the imaging system.

Echocardiography, Doppler, Color↗

PubMed1999

[The significance of the Doppler techniques -- "color Doppler" and "power Doppler" -- in the diagnostic ultrasonography of the eyeball].

The eyeball is perfectly suited for ultrasound examination due to its location and structure. The ultrasound examination including the "color Doppler" and "power Doppler" option was performed in 59 patients. Ophthalmologists requested ultrasound examination in those patients mainly in order to confirm and differentiate retinal ablation or because of opacity of vitreous body of the eye. The ultrasound examination was performed with a Logiq 500 f-y GE unit equipped with a 7.5 MHz linear transducer and a 7.5 MHz linear transducer and a Hitachi 415 EUB applied. Primary retinal ablation was diagnosed in 27 cases, and in 14 cases retinal ablation was caused by a proliferative process. In 18 cases a different pathology was demonstrated including 6 patients in whom we detected an intraocular foreign body.

Adolescent↗

PubMed1998

Comparison of transvaginal color Doppler imaging and color Doppler energy for assessment of intraovarian blood flow.

OBJECTIVE: To investigate any systematic differences in the analysis of blood flow velocity waveforms derived by color Doppler imaging and color Doppler energy examination of corpora lutea and adnexal tumors, to test whether the accuracy for diagnosing ovarian malignancy differs between end points derived by color Doppler imaging and color Doppler energy, and to compare the reproducibility of flow velocity waveform analysis obtained by both methods. METHODS: Fifty-six asymptomatic women with presumed corpora lutea and 67 women with known adnexal masses were included in the study. They all were examined using transvaginal sonography with color Doppler imaging and color Doppler energy. Pulsed Doppler sonography was used to obtain flow velocity waveforms to determine the pulsatility index (PI), resistance index (RI), peak systolic velocity, and time-averaged maximum velocity. The tumors were classified retrospectively according to histologic criteria. RESULTS: There were 52 women with benign, three with borderline, and 12 with malignant ovarian tumors. Repeated-measures analysis of variance revealed no systematic differences in the values of all four measurements performed under color Doppler imaging and color Doppler energy for all cases of corpora lutea and adnexal tumors (PI: P=.153, RI: P=.197, peak systolic velocity: P=.355, time-averaged maximum velocity: P=.159). All cases of borderline and malignant tumors had detectable pulsatile blood flow with color Doppler imaging and color Doppler energy. Forty-two (80.8%) of the benign tumors had flow detectable with color Doppler imaging, compared with 40 (76.9%) with color Doppler energy (P=.480). Analysis of receiver operating characteristic curves showed a marginal but nonsignificant improvement in diagnostic performance with color Doppler energy compared with color Doppler imaging for all four measurements (PI: P=.182, RI: P=.178, peak systolic velocity: P=.254, time-averaged maximum velocity: P=.238). The intraclass correlation coefficients for all four measurements were superior with color Doppler imaging compared with color Doppler energy. CONCLUSION: Flow velocity waveform analysis and diagnostic accuracy for ovarian malignancy are not significantly different between color Doppler imaging and color Doppler energy. Examinations with color Doppler imaging appear to be more reproducible than those with color Doppler energy.

Adult↗

PubMed2000

Comparison of harmonic and conventional power Doppler ultrasonography for assessment of slow flow in hyperechoic tissue: experimental study using a Doppler phantom.

RATIONALE AND OBJECTIVES: Despite the advantages of depicting slow flow in small vessels, conventional power Doppler ultrasound (US) has a basic limitation, specifically that artifactual power Doppler signals mimic blood flow, especially in hyperechoic tissue. The purpose of this study was to compare harmonic power Doppler US with power Doppler US using a Doppler phantom under various parameter settings, focusing on the assessment of slow flow in the hyperechoic tissue. METHODS: While controlling the flow velocity (5 and 10 cm/s), pulse repetition frequency (500, 700, and 1,000 Hz), wall filter (low and medium), and Doppler gain (90%, 96%, and 100%), the authors performed both harmonic Doppler US and power Doppler US by using a Doppler phantom/flow control system. We measured and compared the relative intensities of the Doppler signals (0-250 scale) in both the vessels and hyperechoic tissue-mimicking materials with the two different imaging modalities. RESULTS: Power Doppler US with any combination of the four parameters evaluated depicted strong flow signals (mean, 213) that were superior to harmonic Doppler US (mean, 61). Relatively strong artifactual signals within the hyperechoic tissue-mimicking materials were noted on all power Doppler US studies (mean, 106) but nearly none on harmonic Doppler US (mean, 3). The contrast-to-noise ratio of harmonic Doppler US was significantly greater than that of power Doppler US. CONCLUSIONS: Harmonic Doppler US is more useful in assessing slow flow in hyperechoic tissue than power Doppler US because it produces fewer artifactual Doppler signals originating from stationary hyperechoic tissues, which can be misjudged as true signals on power Doppler US.

Blood Flow Velocity↗

PubMed1998

Intratumoral vascularity of experimentally induced VX2 carcinoma: comparison of color Doppler sonography, power Doppler sonography, and microangiography.

RATIONALE AND OBJECTIVES: Tumor vascularity is useful for characterizing tumors and determining tumor management. The recent development of power Doppler sonography has enhanced the sensitivity of color Doppler imaging in the detection of blood flow because of low power noise and less angle dependence. The purpose of this study was to compare the capability of color and power Doppler sonography with that of microangiography for showing tumor vascularity of VX2 carcinoma. METHODS: Color and power Doppler sonography was performed on VX2 carcinomas in the rabbit thighs, and their findings were correlated with those of microangiography. For qualitative analysis, tumor vascularity was categorized into four items including distribution of tumor vessels, crowdedness of vessels, small vessels, (> or = 0.1 mm), and micro-vessels (< 0.1 mm). Tumor blood flow signals of color Doppler sonography and power Doppler sonography were graded as 3, 2, 1, and 0 and were compared with tumor vascularity on microangiography. For quantitative analysis, percentages of tumor vascular area per tumor area on each study were compared. RESULTS: The mean scores of tumor vascularity on power Doppler sonography were 2.87, 2.73, 2.93, and 2.73 in tumor vascular distribution, crowdedness of vessels, small vessels, and micro-vessels, respectively. Those on color Doppler sonography were 2.4, 2.2, 2.8, and 1.67, respectively. Power Doppler sonography was statistically superior to color Doppler sonography in displaying tumor vascular distribution (P < 0.05) and micro-vessels (P < 0.01). The means and medians of percentages of tumor vascular area per tumor area were 22.7% and 23.5% on microangiography, 17.9% and 21.4% on color Doppler sonography, and 36.4% and 34.7 % on power Doppler sonography, respectively. Percentages of tumor vascular area per tumor area on both color Doppler sonography (r = 0.70) and power Doppler sonography (r = 0.84) were well correlated with those on microangiography. CONCLUSIONS: Power Doppler sonography can demonstrate the tumor vascularity on microangiography relatively well, however, it tends to overestimate the blood flow signals. Color Doppler sonography may have some limitations in imaging tumor vascular distribution and micro-vessels and tends to underestimate tumor vascularity, but can display the blood flow direction. Therefore, power Doppler and color Doppler sonography could complement each other in demonstrating the tumor vascularity.

Angiography↗

PubMed2004

Comparison of continuous wave Doppler ultrasound of the radial artery and laser Doppler flowmetry of the fingertips with sympathetic stimulation.

Laser Doppler is widely used to evaluate sympathetic vasoconstrictor function. Continuous wave (cw)-Doppler of the radial artery may be an alternative but less expensive approach to quantify sympathetically induced resistance changes in the peripheral vascular system. In order to compare the power of both methods, this study was performed with simultaneous assessment of cw Doppler and laser Doppler flowmetry in volunteers. Twenty-five healthy subjects (median age years, range 20-27) rested in a relaxed supine position and were asked to perform a deep inspiratory gasp and a commanded cough (DIG + C). Radial artery blood flow was assessed with a standard cw Doppler device, arteriolar blood flow was assessed simultaneously employing a single point laser Doppler perfusion monitor at the fingertips. We quantified the latency between stimulus and onset of vasoconstriction, the latency to the maximum vasoconstriction and the duration of response. The decrease in flow velocities (cw Doppler) after stimulus was compared with the decrease in capillary flow (laser Doppler). While the flow profile as measured with laser Doppler remained monophasic after stimulation, cw Doppler showed biphasic flow (or absent diastolic flow) in all subjects after DIG + C. The latencies between stimulus and onset of reaction were significantly shorter when measured with laser Doppler (1.8 s vs. 2 s, p = 0.049), the latencies till the maximum extent of the reaction was reached did not differ significantly (3.2 vs. 3.3 s). The duration of the response was significantly shorter when measured by laser Doppler (12.0 vs. 14.5 s (p < 0.0001). While skin blood flow in the laser Doppler measurement decreased after stimulation from 654 flux units (FU) to 319 FU (-59%), mean flow velocities in the radial artery declined from 1.07 kHz to 0.14 kHz (-87%). This relative change was significantly different (p < 0.0001). The correlation between the decline of flux units as measured by laser Doppler and cw Doppler changes was r = 0.616 (p = 0.004). Both methods are feasible to monitor flow changes due to sympathetic stimulation. Latencies and relative quantitative changes were closely correlated.Thus, cw Doppler is a valid alternative approach to laser Doppler flowmetry in healthy volunteers.

Adult↗