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PubMed1986

Echo-Doppler velocimeter in the diagnosis of hypertensive patients: the renal artery Doppler technique.

The renal blood flow velocity characteristics in 8 normal controls, 19 essential hypertensive patients and 8 hypertensive patients with renovascular disease were evaluated using echo-Doppler velocimetry. Two different approaches for ultrasonic detection of the renal artery, the translumbar and the transabdominal approach, were used. Renal Doppler sonograms were analyzed by measuring the acceleration index and the peak-systolic frequency/end-diastolic frequency (S/D) ratio. Renovascular patients who required surgery were examined before and after angioplasty. Doppler signals could be detected in all 35 subjects by using the translumbar approach. The acceleration index of the affected renal arteries significantly correlated to the percent stenosis of the renal artery determined by angiography. The acceleration index in the affected renal artery was improved by surgical treatment. The S/D ratio in essential hypertensives was significantly higher than that in the normal controls. There was a significant inverse correlation between the S/D ratio and creatinine clearance. Echo-Doppler velocimetry is considered to be useful in the diagnosis of renovascular disease and also in the evaluation of abnormalities of renal vascular resistance in hypertensive patients.

Adolescent↗

PubMed1992

[New aspects in the evaluation of Doppler blood flow curves: three- dimensional image and analysis of Doppler shift frequencies within the heart cycle].

Since the introduction of Doppler ultrasound to the area of medical diagnostics, there have been numerous improvements and important technical refinements. In obstetrics, Doppler examination allows a more accurate and encompassing evaluation of the foetal condition than was previously possible. Combined with today's sophisticated computer technology, it has a great potential in research and to expand our knowledge about the physiology and pathophysiology of foetal and maternal haemodynamics. This paper describes a new way of integrating another factor into the evaluation of Doppler blood flow waveforms, namely, the intensities of various frequencies. One result should be more detailed information about the given haemodynamic situation; another, a valuable tool for the quality control of Doppler blood flow measurements. Although our work was on applications in the field of obstetrics, the method we have developed can be used in all medical areas.

Blood Flow Velocity↗

PubMed2005

The effects of maintenance recombinant human erythropoietin therapy on ambulatory blood pressure recordings: conventional, Doppler, and tissue Doppler echocardiographic parameters.

Cardiovascular disease is the major cause of mortality in maintenance hemodialysis patients. Left ventricular dysfunction is present in approximately 80% of these patients and is highly predictive of future ischemic heart disease, cardiac failure, and death. Anemia has been identified as one of several risk factors responsible for cardiac complications. The treatment of renal anemia with recombinant human erythropoietin (rHuEpo) and consequent improvement of cardiac performance may reverse pathological changes in left ventricular geometry. In this study, the acute and chronic effects of rHuEpo administration on 24-hour ambulatory blood pressure recordings and echocardiographic parameters in 30 rHuEpo-naïve maintenance hemodialysis patients were examined. Twenty-four-hour ambulatory blood pressure monitoring was performed prior to and after 1 week and 6 months of rHuEpo administration. The patients underwent echocardiographic examination prior to and after 6 months of rHuEpo administration. One week treatment with rHuEpo did not cause any significant change in 24-hour ambulatory blood pressure recordings. After 6 months of therapy, serum hemoglobin levels increased from 8.8 +/- 0.66 g/dL to 10.8 +/- 0.70 g/dL (P < 0.05). Echocardiographic examination revealed elevation in ejection fraction (62.26 +/- 6.84% vs. 69.90 +/- 8.98%, P < 0.05) with reductions in fractional shortening (36.70 +/- 4.96% vs. 35.96 +/- 6.32%, P < 0.05), interventricular septum thickness (1.21 +/- 0.16 vs. 1.00 +/- 0.16 cm, P < 0.05), and left ventricular mass index (148.2 +/- 46.5 g/m2 vs. 93.6 +/- 17.2 g/m2, P < 0.05). Doppler echocardiography and tissue Doppler imaging provided additional information in comparison with conventional echocardiography. Before treatment, mitral flow E wave (E, 0.64 +/- 0.27 vs. 0.82 +/- 0.17 cm/s), mitral flow A wave (A, 0.80 +/- 0.21 vs. 0.70 +/- 0.21 cm/s), early diastolic velocity of lateral wall (Lateral E', 11.2 +/- 2.8 vs. 12.4 +/- 2.3 cm/s), late diastolic velocity of lateral wall (Lateral A', 6.7 +/- 2.5 vs. 7.8 +/- 2.1 cm/s), early diastolic velocity of septal wall (Septal E', 9.7 +/- 2.9 vs. 11.3 +/- 1.1 cm/s), and late diastolic velocity of septal wall (Septal A', 6.4 +/- 2.1 vs. 7.8 +/- 2.0 cm/s) were significantly lower in patients than in the controls. Patients and controls have similar deceleration time of mitral flow E wave (E Dec, 186 +/- 57.8 vs. 192 +/- 62.4 ms), isovolumic left ventricular relaxation time (IVRT, 111.9 +/- 30.7 vs. 91.1 +/- 32 ms), systolic velocity of lateral wall (Lateral S', 7.8 +/- 2.3 vs. 8.1 +/- 2.0 cm/s), and systolic velocity of septal wall (Septal S', 7.5 +/- 1.9 vs. 7.7 +/- 1.4 cm/s) values. Therapy with rHuEpo did not cause significant changes in E (0.64 +/- 0.27 vs. 0.76 +/- 0.29 cm/s), A (0.80 +/- 0.21 vs. 0.79 +/- 0.23 cm/s), E Dec (186 +/- 57.8 vs. 165.8 +/- 60.1 ms), IVRT (111.9 +/- 30.7 vs. 101.6 +/- 36.2 ms), Lateral E' (11.2 +/- 2.8 vs. 11.5 +/- 4.4 cm/s), Lateral A' (6.7 +/- 2.5 vs. 7.4 +/- 2.1 cm/s), Lateral S' (7.8 +/- 2.3 vs. 8.1 +/- 2.0 cm/s), Septal E' (9.7 +/- 2.9 vs. 10.0 +/- 1.1 cm/s), Septal A' (6.4 +/- 2.1 vs. 6.6 +/- 2.0 cm/s), and Septal S' (7.5 +/- 1.9 vs. 7.9 +/- 1.4 cm/s) indicating persistence of diastolic dysfunction. In 6 months time, 24-hour ambulatory blood pressure recordings, however, tended to be higher (systolic: 125.16 +/- 21.02 mm Hg vs. 134.36 +/- 23.98 mm Hg; diastolic: 77.40 +/- 14.47 mm Hg vs. 83.26 +/- 14.89 mm Hg, P < 0.05). Correction of anemia with rHuEpo results in the elevation of blood pressure and reduction in left ventricular mass index. Myocardial contraction and relaxation velocities did not improve following regression of left ventricular hypertrophy, suggesting the persistance of diastolic dysfunction. Doppler echocardiography with tissue Doppler imaging reflects the real situation of diastolic function in patients on maintenance hemodialysis.

Anemia↗

PubMed1992

[Color Doppler flow imaging and duplex Doppler in the examination of primary liver cancer].

We examined 40 cases of primary liver cancer with color doppler flow imaging and duplex doppler. In 20 cases, there was arterial flow in the tumor. In 17 cases, there was arterial and portal venous flow in the tumor. In 22 cases, there was arterial flow entering the tumor from its surroundings. In 28 cases, the right or left hepatic artery was dilated. We compared the results of digital subtraction angiography with the doppler ultrasound in 28 cases and found the difference was not significant (chi 2 = 1.05, P greater than 0.05). Therefore, we believe that the doppler ultrasonography is the method of choice in the diagnosis of primary liver cancer.

Adolescent↗

PubMed1988

[Comparison of the results of umbilical artery velocimetry obtained by pulsed Doppler and continuous Doppler].

Doppler assessment has become the fashion in obstetric screening at present and this is absolutely justified in view of the quality of the information that is obtained. The authors have tried to assess the two methods of analysing the blood flow through the umbilical artery by using pulsed Doppler and continuous Doppler techniques. They have used a fairly new statistical method (differential). The authors have found that the methods are interchangeable. They did this on 32 patients who on the same day had pulsed and continuous Doppler tests and they used Pourcelot's placental resistance technique. These observations show that consistent diagrams which are equivalent to one another are obtained by the two methods and they can be used economically.

Female↗

PubMed1998

Differentiation of benign and malignant tumors of the parotid gland: value of pulsed Doppler and color Doppler sonography.

To establish criteria for the differentiation of benign and malignant tumors of the parotid gland using color Doppler sonography (CDS) and pulsed Doppler sonography (PDS) we examined 37 patients with parotid tumors by gray-scale ultrasound, CDS, and PDS. Tumor vascularization displayed by CDS was graded subjectively on a 4-point scale (0 = no vascularization, 3 = high vascularization). From the Doppler spectrum, the highest systolic peak flow velocity, the resistive index (RI), and the pulsatility index (PI) were calculated. There were 11 malignant and 26 benign tumors. Tumor vascularization by CDS was grade 0 or 1 in 88.5% of benign lesions, whereas it was grade 2 or 3 in 82% of malignant lesions (P < 0.0001). The highest systolic peak flow velocity was statistically significantly higher in malignant lesions than in benign lesions. Using a threshold systolic peak flow velocity of 25 cm/s, sensitivity was 72% and specificity was 88% for the detection of a malignant tumor. Evaluation of tumor vascularization by CDS and PDS cannot differentiate between benign and malignant parotid tumors with certainty. However, high vascularization and high systolic peak flow velocity in tumor vessels should raise the suspicion of malignancy, even if tumor morphology on gray-scale sonography indicates a benign lesion.

Adenolymphoma↗

PubMed2000

Central retinal artery color Doppler monitoring versus transcranial Doppler monitoring in cardiac surgery.

We hypothesized that the central retinal artery color Doppler (CRAD) technique can be used as an alternative monitoring method to the conventional transcranial Doppler (TCD) technique which does not consistently provide good signals during cardiopulmonary bypass. This is the first study to compare CRAD with TCD during cardiac surgery. Twenty patients without stroke were examined at the seven preset stages of the two procedures. The maximum flow velocity (Vmax) of the right central retinal artery was measured with a 7.5-MHz Doppler system. The Vmax of the right middle cerebral artery was measured with a TCD system. To estimate the relationship between Vmax and maximum blood pressure (BPmax), CRAD-Vmax (6.6 +/- 2.2 cm/s), TCD-Vmax (44.0 +/-14.8 cm/s), and BPmax (114 +/- 28.5 mmHg) obtained at the initial stage were normalized. The Vmax values of CRAD were successfully obtained, at each of the seven study stages, in all 20 patients. The Vmax values of TCD were obtained at 125 points, and 15 missing values were seen during the stages of cardiopulmonary bypass. CRAD-Vmax was correlated to TCD-Vmax (r = 0.775, P < 0.0001). The normalized values of both TCD- and CRAD-Vmax were correlated to the normalized BPmax (r = 0.766, P < 0.0001) (r = 0.787, P < 0.0001). The accuracy of CRAD was confirmed by the significant correlation with TCD.

Adolescent↗

PubMed1997

Requirement for accurate measurement of regurgitant stroke volume by the combined continuous-wave Doppler and color Doppler flow convergence method.

The examination conditions necessary for accurate measurement of regurgitant volume by the proximal flow convergence method applying a simple hemispheric equation remain uncertain. This study investigated the requirement for measuring regurgitant stroke volume from the combined continuous-wave and color Doppler proximal flow convergence approach. Twenty-five pulsatile flow rates were produced by driving five regurgitant stroke volumes ranging from 30 to 70 ml/beat through planar orifices with cross-sectional areas ranging from 0.10 to 1.0 cm2. Four different shaped orifices (circular, rectangular with a major/minor axis ratio 2:1, slitlike with a major/minor axis ratio of 8:1, and square) having identical orifice areas (0.5 cm2) were examined. Regurgitant volume (RV) was estimated from the combined continuous-wave and color Doppler approach according to the previously described equation RV = 2 pi x (r max)2 x AV x (TVI/Vmax), where r max is maximal radial distance, AV is aliasing velocity, TVI is time velocity integral of regurgitant jet, and Vmax is peak velocity of regurgitant jet. Plotting the difference between actual and calculated RV versus radial distance of the proximal convergence shell for each flow rate from circular to rectangular orifices yielded curves conforming to a curvilinear function that crossed the point of zero difference at 1.0 cm. However, in the slitilke orifice, a more remote distance (1.6 cm) is required for the best agreement. Actual regurgitant stroke volume can be estimated well by the combined continuous-wave Doppler and proximal flow convergence method applying a simple hemispheric equation if an aliasing velocity is used that results in a radial distance of at least 1.0 cm.

Confounding Factors, Epidemiologic↗

PubMed1995

Cerebral blood flow and resistances during hypotensive haemorrhage in the rabbit: transcranial Doppler and laser-Doppler flowmetry.

Transcranial Doppler (TCD) determined cerebral blood flow velocity and laser Doppler flowmetry (LDF) measured cortical perfusion were simultaneously assessed during hypotensive haemorrhage in 15 anaesthetized rabbits. Systolic (Fsys), diastolic (Fdia) and mean (Fmean) blood flow velocities were recorded into the intracranial internal carotid (ICA) and basilar artery (BA). Resistance (RI = Fsys-Fdia/Fsys) and pulsatility (PI = Fsys-Fdia/Fmean) indices were calculated. Step decreases of 10 mmHg of mean arterial pressure (MAP) from 80 to less than 30 mmHg provoked a fall of LDF signal below 50 mmHg. Blood velocities decreased into BA below 40 mmHg, and below 50 mmHg into ICA indicating regional differences in cerebral autoregulation. Cortical resistances (resLDF = MAP/LDF) fell below 60 mmHg whereas RI and PI increased when MAP decreased into BA below 40 mmHg and ICA below 50 mmHg. A weak correlation was found between Fmean and LDF (BA: r = 0.55, P < 0.01 and ICA = 0.46, P < 0.01). Both RI and PI were poorly correlated to resLDF into BA (RI-resLDF: r = -0.39, P < 0.01; PI-resLDF: r = -0.39, P < 0.01) and ICA (RI-resLDF: r = -0.18, ns; PI-resLDF: r = -0.22, ns). Pulse pressure (systolic-diastolic pressure) correlated with RI (ICA: r = -0.62, P < 0.001; BA: r = -0.61, P < 0.001) and PI (ICA: r = -0.61, P < 0.001; BA: r = -0.62, P < 0.001). In conclusion, during haemorrhagic shock, TCD correlates with LDF and indicates regional differences in autoregulatory settings. However, Doppler indices do not reflect the changes in cerebral resistances because they are influenced by the changes in pulsatile pressure.

Anesthesia↗

PubMed1997

Spontaneous intrahepatic portosystemic venous shunt in a patient with cirrhosis: diagnosis by combined color Doppler and pulsed Doppler ultrasonography.

Large spontaneous intrahepatic portosystemic venous shunts are occasionally found and their diagnosis by Doppler sonography is rarely reported. The authors describe a case of spontaneous intrahepatic porto-systemic venous shunt in liver cirrhosis diagnosed by color Doppler and characterized by an unusual pulsed Doppler spectrum: a continuous flat portal-like pattern of flow in the portal branch, and in both the shunt and the hepatic vein.

Aged↗

PubMed2003

[Validation of a new hand-carried ultrasound device equipped with directional color power Doppler and continuous wave Doppler].

OBJECTIVES: This study evaluated the accuracy of the directional color power Doppler (DCPD) and continuous wave Doppler (CWD) methods incorporated in the new hand-carried SonoSite 180PLUS ultrasound device. METHODS: The hand-held ultrasound system with 2.5 MHz transducer and SONOS 5500 was used as a standard ultrasound system with a 2 to 4 MHz wideband transducer. The experimental study used a Doppler wire phantom to evaluate the influence of target wire speed and angle of transducer on DCPD imaging. The clinical study included 48 consecutive patients. DCPD assessment of valvular regurgitation measured the distances of DCPD signals of mitral, aortic and tricuspid valve regurgitation using the apical four-chamber view for comparison with standard echocardiography. CWD assessment measured the peak velocities of the aortic flow and tricuspid valve regurgitant flow for comparison with standard echocardiography. RESULTS: In the experimental study, DCPD signals were not influenced by target wire speed changes and transducer incident angles. In the clinical study, agreements for mitral, aortic and tricuspid regurgitation between the two methods were 89.6%, 81.8% and 78.7%, respectively. The distances of DCPD valve regurgitant signals by the hand-carried ultrasound device showed good correlation (mitral regurgitation: y = 0.84x + 0.55; r = 0.93, aortic regurgitation: y = 0.95x + 0.27; r = 0.94, tricuspid regurgitation: y = 0.86x + 0.61; r = 0.90) with those by standard echocardiography. Evaluation of CWD velocity measurements showed good agreement for the lower flow velocities (< 2.0 m/sec). However, underestimation occurred for the high flow velocities (> 2.0 m/sec) compared with those by standard echocardiography (aortic flow: y = 0.80x + 0.11; r = 0.95, tricuspid regurgitation: y = 1.00x - 0.23; r = 0.90). CONCLUSIONS: The new hand-carried ultrasound device (SonoSite 180PLUS equipped with DCPD and CWD) is clinically useful for evaluating valvular regurgitations and flow velocities. Further studies are needed to determine the mechanism of the underestimation of high flow velocities by CWD.

Aortic Valve Insufficiency↗

PubMed1994

[Preoperative evaluation of resectability of hilar bile duct carcinoma by color Doppler flow imaging and duplex Doppler].

Color flow images of hilar bile duct carcinoma and the relationship between tumors and hilar important blood vessals were observed in 22 patients with hilar bile duct carcinoma by color Doppler flow imaging (CDFI) and Duplex Doppler. It was found that most of bile duct carcinoma were of oligovascularity. Accurate rate were 81.82% and 77.28% respectively by preoperative ultrasound evaluation of the relationship between the tumor and the portal vein, and the tumor and the hepatic artery. CDFI and Duplex Doppler are sensitive, convenient and noninvasive methods for preoperative evaluation of resectability of hilar bile duct carcinoma and provide important information for surgery.

Adult↗

PubMed1998

Breast masses: color Doppler, power Doppler, and spectral analysis findings.

PURPOSE: To determine the diagnostic efficacy of power Doppler sonography (PDS) with spectral analysis for breast diseases, we retrospectively compared PDS and color Doppler sonography (CDS) in patients with breast lesions. METHODS: One hundred thirty-eight women with palpable breast lesions were examined with PDS (65 women) and/or CDS (73 women). We calculated peak velocity, end-diastolic velocity, pulsatility index (PI), and resistance index (RI). RESULTS: On a 4-point subjective visual vascularity scale, PDS demonstrated higher vascularity than did CDS. Although smaller and more subtle vessels could be detected only with PDS, the PI and RI differed significantly between malignant and benign lesions when either PDS or CDS was used. However, logistic regression analysis showed that high PI and RI were associated with malignancy only when CDS was used. When PDS was used, PI was significantly higher in invasive ductal carcinomas with fibrous stroma and ill-defined margins (associated with a poor prognosis) than in invasive ductal carcinomas without fibrous stroma or with well-defined margins. CONCLUSIONS: Doppler spectral analysis of malignant breast lesions using PDS may contribute to the determination of prognosis.

Breast Neoplasms↗

PubMed1999

[Analysis of mitral annulus excursion with tissue Doppler echocardiography (tissue Doppler echocardiography = TDE). Noninvasive assessment of left ventricular, diastolic dysfunction].

BACKGROUND: Mitral inflow velocity, deceleration time, and isovolumic relaxation time recorded by Doppler echocardiography have been widely used to evaluate left ventricular diastolic function but are affected by age, heart rate, loading conditions, and other factors. The diastolic mitral anulus velocity assessed by tissue Doppler echocardiography (TDE) was suggested to provide additional information about LV relaxation less affected by filling pressures. AIM OF THE STUDY: This study was designed to assess the clinical utility of mitral anulus velocity in the evaluation of left ventricular diastolic function. PATIENTS AND METHODS: Three groups of patients with a systolic ejection fraction > 45% were separated: 10 normal volunteers (60 +/- 10 y, CON group), 15 asymptomatic patients with known coronary artery disease (60 +/- 11 y, CAD group) and 15 patients with long-term arterial hypertension and heart failure symptoms (58 +/- 9 y, HYP group). The mitral inflow profile (E, A, E/A) was measured by pulsed Doppler, and the deceleration time (DT) and the isovolumic relaxation period (IVRT) were calculated. Systolic, early, and late diastolic velocities of the septal mitral anulus (ST, ET, AT, ET/AT) were assessed by pulsed TDE. All study subjects had invasive measurements of left ventricular end diastolic filling pressures during left heart catheterization. RESULTS: In the AH group, ET (6.9 +/- 4.8 cm/s) and ET/AT (0.71 +/- 0.28) were reduced compared to the CON group (11.7 +/- 4.7 cm/s and 1.11 +/- 0.36, p < 0.05, respectively) and the CAD group (8.9 +/- 5.4 cm/s and 0.85 +/- 0.26, respectively, p = ns). The groups did not differ with respect to the mitral E/A ratio, the deceleration time and the isovolumic relaxation time. LVED in the HYP group (16 +/- 8 mm Hg) was elevated compared to the CON group (8 +/- 3, p < 0.05) and the CAD group (12 +/- 6 mm Hg, p = ns). No correlation was found between ET and LVED (r = 0.26). When the combination of mitral E/A ratio > 1 with LVED > or = 15 mm Hg was classified as pseudonormalization, the pseudonormalization could be identified by a peak early diastolic mitral anulus velocity (ET) < 7 cm/s and an ET/AT ratio < 1 with a sensitivity of 77% and a specificity of 88%. CONCLUSIONS: The early diastolic mitral anulus velocity assessed by TDE (ET) is a preload-independent index of LV relaxation. TDE permits the detection of diastolic dysfunction in patients with a pseudonormal mitral inflow and elevated filling pressures.

Adult↗

PubMed1995

Monitoring intracranial dynamics by transcranial Doppler--a new Doppler index: trans systolic time.

Since the introduction of transcranial Doppler sonography (TCD) several investigators have described the relationship between raised intracranial pressure (ICP) and Doppler waveform. This waveform has been expressed by several indices, such as the pulsatility index (PI) and the resistance index (RI). These indices are used to demonstrate the presence of raised ICP. In childhood hydrocephalus this information can be used to indicate the need for shunt implantation. However, PI and RI do prove to have certain disadvantages as both are strongly influenced by the heart rate. Moreover, both indices have a broad range of reference values, especially in children. Therefore, they are not very reliable for detecting insidious changes in the ICP. These drawbacks are due to the fact that these indices are composed of blood flow velocity measurements and do not embody the slope of the TCD waveform itself. An ideal TCD waveform analysis should be performed concerning the time-related changes of the velocities. We present a hydrodynamic model, with its electrical analogue, which shows the effects of raised ICP on the intracranial hemodynamic system. Based on these physical findings we define a new Doppler index, the Trans Systolic Time, reflecting specific changes in the TCD waveform induced by changes in the mean ICP. The applicability of this index, compared with PI and RI, is illustrated by consecutive simultaneous TCD and AFP measurements in three children with hydrocephalus.

Blood Flow Velocity↗

PubMed1994

A new Doppler imaging measurement in aortic stenosis: the contour length of the jet origin flow area. Relationships between both, with usual Doppler data and left ventricular hypertrophy.

Planimetry of stenotic aortic jet origin flow areas was performed using transthoracic Doppler imaging, with measurement of the contour length of flow areas and calculation of a contour/area (C/A) Doppler ratio on a group of 75 patients with aortic stenosis ranging from 0.27 to 2.44 cm2. The purpose was to study correlations of these data with the usual Doppler data and with left ventricular hypertrophy. The "r" coefficient between planimetered flow areas and those calculated by the continuity equation method was 0.89. Mean values (SD) of data were: areas: (planimetry) 1.00 +/- 0.53 cm2, (continuity equation) 0.91 +/- 0.42 cm2, contours: 5.6 +/- 1.6 cm, C/A: 0.66 +/- 0.25, maximal and mean pressure gradients: 68 +/- 34 and 37 +/- 21 mmHg, left ventricular hypertrophy: 138 +/- 30 g/m2 BSA (vs. 100 +/- 18 in normals). All values except age, gender and BSA, differed significantly (p < 0.001) between areas below or over 0.85 cm2. Other correlations between parameters were significant (p < 0.01 to 0.001), but with lower "r" coefficients due to widely scattered individual values. Contours increased much less rapidly than areas did, and were correlated with left ventricular hypertrophy only when coupled in the C/A ratio, with a higher "r" coefficient (0.62) than areas alone (0.52). Study of both areas and contours helps to approach the geometry of the orifice. This suggests that the individual geometry of the stenosis might weigh on the left ventricular mass growth, as an associated factor for a given decrease in stenotic area.

Adult↗

PubMed1996

Accuracy of color doppler velocity in the flow field proximal to a regurgitant orifice: implications for color doppler quantitation of valvular incompetence.

Color Doppler is routinely used in estimates of valvular regurgitation. Velocity and subsequently flow measurements are made at about 7-10 cm from the ultrasonic transducer. Error in velocity measurement may occur due to spatial broadening of the color Doppler beam in the axial, azimuthal and lateral directions. Error in velocity may also occur due to wall filters since the filtering process is not uniform throughout the velocity range indicated by the color bar. An attempt to estimate this error was made using an in vitro orifice model, a numerical finite element model (FEM), and information from the manufacturer. We found that the acoustic beam spatial expansion, wall filter sensitivity and Nyquist limit (NYL) have to be considered simultaneously to account for errors. The combined spatial expansion and wall filter effect on velocity was estimated as a weighted average over the sample volume. The error distributions are not universal but depend on orifice size and flow. For a 3-mm orifice and 100 cm s NYL the overall effect was overestimation of low velocities and significant underestimation of high velocities due to the high velocity gradients inside the sample volume. For the 5- and the 10-mm orifice the effect was less accentuated. Based on this overall error distribution, a correction was incorporated on color Doppler obtained data. The incorporated correction yielded better agreement with numerical velocity data. This correction is important in the application of the proximal isovelocity surface area (PISA) technique and the evaluation of regurgitant flowrates.

Blood Flow Velocity↗

PubMed2004

Quantification of ovarian stromal Doppler signals in poor responders undergoing in vitro fertilization with three-dimensional power Doppler ultrasonography.

OBJECTIVE: This was a prospective comparative clinical study to test the hypothesis that the decreased ovarian sensitivity to gonadotropins observed in women embarking on an in vitro fertilization (IVF) treatment may be due to changes in ovarian stromal blood flow. STUDY DESIGN: Three-dimensional (3D) power Doppler ultrasonographic indexes were used to quantify ovarian stromal blood flow and vascularization in poor responders. Forty patients undergoing an IVF cycle were collected and divided into two groups, a poor responder group (n=17) (estradiol <600 pg/mL or < or =3 oocytes retrieved) and normal responder group (n=23), based on their response to a standard down-regulation protocol for controlled ovarian stimulation. During ovarian stimulation, on the day of administration of human chorionic gonadotropin (HCG), patients underwent hormonal (serum E2), ultrasonographic (follicular number and diameter), and 3D power Doppler (ovarian stromal blood flow) evaluation. RESULTS: Compared with poor responders, the serum estradiol levels on the day of administration of HCG, the number of follicles more than 14 mm, the number of oocytes retrieved, the number of embryos transferred, and the pregnancy rate were significantly higher in normal responders. The Vascularization Index, Flow Index, and Vascularization Flow Index were significantly lower (P<.05) in the poor responder (0.13+/-0.11, 30.89+/-10.35, and 0.05+/-0.04, respectively) compared with the women with a normal response (1.20+/-1.10, 43.88+/-7.77, and 0.61+/-0.57, respectively). CONCLUSION: The 3D power Doppler indexes of ovarian stromal blood flow in poor responders was significantly lower than normoresponders. This may help to explain the poor response during HCG administration in controlled ovarian stimulation.

Adult↗