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At least 145 records · Page 8Linked to original sources

PubMed2003

Diastolic dysfunction in an unusual case of cardiomyopathy in a child: insights from Doppler and Doppler tissue imaging analysis.

OBJECTIVES: This case report describes an unusual form of cardiomyopathy in a child with abnormalities in both ventricular relaxation and compliance. The diastolic abnormalities are well-defined using Doppler inflow velocities and Doppler tissue imaging, and the Doppler findings are correlated with intracardiac pressure measurements. This case illustrates the use of noninvasive Doppler techniques in identifying diastolic dysfunction, and it sheds additional light on the interplay of relaxation, compliance, and heart rate in creating the variable inflow Doppler patterns encountered clinically.

Cardiomyopathy, Hypertrophic↗

PubMed1987

Comparison of laser Doppler and Doppler ultrasound in lower limb vascular diagnosis.

This study represents a preliminary investigation into the use of laser Doppler flowmetry in lower limb vascular diagnosis. The method is compared with the accepted method of continuous wave Doppler ultrasound. Fifty-six patients with symptoms of lower limb vascular disease were investigated consecutively and independently using both techniques. In approximately two-thirds of patients the two methods showed broad agreement in their classification of disease severity (correlation coefficient = 0.63, P less than 0.001, n = 41). However, about 30% of those studied had impaired microvascular responses on laser Doppler evaluation with no detectable major vessel disease on continuous wave ultrasound investigation. The results indicate that more information is obtained about a subject's vascular status when results from both methods are combined. Thus laser Doppler flowmetry may be useful adjunct to Doppler ultrasound and segmental pressure measurements in the vascular laboratory.

Adult↗

PubMed1997

Intraplacental spectral Doppler scanning: fetal growth classification based on Doppler velocimetry.

The purpose of the study was to develop a Doppler modality for effective assessment of the fetoplacental circulation. Calculations based upon a theoretical model were employed to predict downstream pulsatility values in the fetoplacental circulation. The clinical study included 83 pregnancies between 32 and 36 weeks of gestation. Sixty-nine women were recruited from our low-risk clinic and had uncomplicated pregnancies. Fourteen patients had complications suspected to be associated with placental pathology. All 83 patients demonstrated UA Doppler indices within the normal limits for the gestational age. The study induced intraplacental and UA Doppler waveform analyses. The ratios between intraplacental and UA PI values (at the cord insertion to the placenta) were calculated. Nineteen patients with intraplacental to UA (placental cord insertion) PI ratios > 1 (abnormal) had adverse pregnancy outcome. The study demonstrates the importance of detailed scanning of the intraplacental pulsatile waveforms and the importance of using the ratio between the intraplacental and UA Doppler indices as an additional method for evaluation of the fetoplacental circulation. The method might be proven more effective mainly in the early stages of placental disease when a relatively small number of the placental terminal arterioles are affected with a negligible effect on the UA Doppler indices, and also in the evaluation of the large placenta. A fetal growth classification based on detailed intraplacental velocimetry and cord to intraplacental flow gradient is proposed.

Adult↗

PubMed1991

Prognostic significance of Doppler measures of diastolic function in cardiac amyloidosis. A Doppler echocardiography study.

BACKGROUND: We have previously characterized the left ventricular diastolic filling abnormalities in cardiac amyloidosis by Doppler methods. The various filling patterns were shown to be related to the degree of cardiac amyloid infiltration. The purpose of this study was to determine the value of Doppler diastolic filling variables for assessing prognosis in cardiac amyloidosis. METHODS AND RESULTS: We performed pulsed-wave Doppler studies of the left ventricular inflow and obtained clinical follow-up data in 63 consecutive patients with biopsy-proven systemic amyloidosis. All patients had typical echocardiographic features of cardiac involvement. The patients were subdivided into two groups according to deceleration time: Group 1 (33 patients) had a deceleration time of 150 msec or less, indicative of restrictive physiology, and group 2 (30 patients) had a deceleration time of more than 150 msec. Of the 63 patients, 32 (51%) died during a mean follow-up period of 18 +/- 12 months. Of these deaths, 25 (78%) were cardiac deaths, and 19 of the 25 patients (76%) were from group 1. The 1-year probability of survival in group 1 was significantly less than that in group 2 (49% versus 92%, p less than 0.001). Bivariate analysis revealed that the combination of the Doppler variables of shortened deceleration time and increased early diastolic filling velocity to atrial filling velocity ratio were stronger predictors of cardiac death than were the two-dimensional echocardiographic variables of mean left ventricular wall thickness and fractional shortening. CONCLUSIONS: Doppler-derived left ventricular diastolic filling variables are important predictors of survival in cardiac amyloidosis.

Amyloidosis↗

PubMed1998

Doppler estimation of left ventricular filling pressure in sinus tachycardia. A new application of tissue doppler imaging.

BACKGROUND: Doppler echocardiography is frequently used to predict filling pressures in normal sinus rhythm, but it is unknown whether it can be applied in sinus tachycardia, with merging of E and A velocities. Tissue Doppler imaging (TDI) can record the mitral annular velocity. The early diastolic velocity (Ea) behaves as a relative load-independent index of left ventricular relaxation, which corrects the influence of relaxation on the transmitral E velocity. METHODS AND RESULTS: We evaluated 100 patients 64+/-12 years old with simultaneous Doppler and invasive hemodynamics. Mitral inflow was classified into 3 patterns: complete merging of E and A velocities (pattern A), discernible velocities with A dominance (B), or E dominance (C). The Doppler data were analyzed at the mitral valve tips for E, acceleration and deceleration times of E, and isovolumic relaxation time. In patterns B and C, the A velocity, E/A ratio, and atrial filling fraction were derived. Pulmonary venous flow velocities were also measured, and TDI was used to acquire Ea and Aa. Weak significant relations were observed between pulmonary capillary wedge pressure (PCWP) and sole parameters of mitral flow, pulmonary venous flow, and annular measurements. These were better for patterns A and C. E/Ea ratio had the strongest relation to PCWP [r=0.86, PCWP=1.55+1.47(E/Ea)], irrespective of the pattern and ejection fraction. This equation was tested prospectively in 20 patients with sinus tachycardia. A strong relation was observed between catheter and Doppler PCWP (r=0.91), with a mean difference of 0.4+/-2.8 mm Hg. CONCLUSIONS: The ratio of transmitral E velocity to Ea can be used to estimate PCWP with reasonable accuracy in sinus tachycardia, even with complete merging of E and A velocities.

Adult↗

PubMed1995

Technical note: comparison of colour Doppler energy sonography with conventional colour Doppler sonography in detection of flow signal in peripheral renal transplant vessels.

The technical advantage of colour Doppler energy sonography (CDE) results in a higher sensitivity for blood flow detection than in conventional colour Doppler sonography (CDI). We compared the efficiency of CDE versus CDI in the detection of blood flow signals in asymptomatic patients after renal transplantation. 10 asymptomatic voluntary patients after renal transplantation were evaluated with CDI and subsequently with CDE by two examiners. Filter, scale and gate setting were kept constant, the Doppler gain was increased individually in every patient until background noise just did not derange the image. The assessment of blood flow signal was done using a self defined score system. CDI showed Doppler signal in the interlobar vessels in all 10 patients and blood flow signal in arcuate arteries and adjacent portions of interlobular vessels in nine of 10 patients. We were not able to detect blood flow related signal in the more peripheral medullary and cortical vessels. CDE obtained blood flow signal in interlobar and interlobular vessels in all patients. In addition, Doppler signal was observed in all patients in small medullary and cortical vessels. CDE increases detection of blood flow related signal in peripherally located small medullary and cortical vessels. There was no improvement in the evaluation of blood flow in interlobar vessels but marked improvement in blood flow detection in small peripherally located vessels. CDE cannot completely replace CDI in the sonographic evaluation of vascular complications in renal transplants, but should be used as an additional measure to rule out pathology in small peripheral renal vessels.

Adult↗

PubMed1992

Doppler cardiac output and left ventricular performance after cardiac surgery. Pulsed Doppler ascending aorta and pulmonary blood flows and left ventricular function using implanted microprobes.

We have developed novel implantable Doppler microprobes to monitor beat-by-beat stroke volume and cardiac output (CO) after cardiac surgery. In 11 adults undergoing either coronary artery bypass grafting (n = 6) or valve replacement (n = 5), Doppler microprobes were implanted on the ascending aorta or the main pulmonary artery to measure aortic blood flow (ABF) or pulmonary artery blood flow (PBF). The diameters of both vessels were determined before surgery using two-dimensional echocardiography. Stroke volume was obtained from velocity tracings measured by a 4-MHz zero-crossing pulsed Doppler flowmeter. Simultaneous measurements of Doppler and thermodilution CO (TDCO) were compared. We found the following: ABF = 1.03 TDCO - 0.22 L/min (r = 0.89); while PBF = 0.69 TDCO - 1.24 L/min (r = 0.75). Furthermore, peak flow velocity and maximum acceleration of blood in the ascending aorta were measured after inotropic stimulation with dobutamine; both values increased significantly from control values (25.2 +/- 6.1 percent and 44.6 +/- 8.6 percent, respectively, at 7.5 micrograms/kg/min). We conclude that implanted aortic Doppler microprobes provide a sensitive and reliable method to measure aortic blood flow velocity after surgery and then allow monitoring of stroke volume and CO and analysis of left ventricular function after cardiac surgery.

Aorta↗

PubMedDate not supplied

[Assessment of microvascularization around the plaques in Peyronie's disease with Doppler color ultrasonography, power Doppler and ultrasonography contrast media].

INTRODUCTION: The origin of Peyronie's disease remains obscure although the first report of this condition dates back to 1743. The disease prevalence in 388.6 in 100,000 population and little physiopathologic information is available. Repeated microtrauma to the tunica albuginea appears to favor the onset of inflammatory phenomena which result in fibrosis and calcification. The disease activity produces a microvascularization around the fibrocalcific plaques. We studied the evolution of the inflammatory process in Peyronie's disease relative to clinical symptoms, in order to optimize treatment follow-up. MATERIAL AND METHODS: We examined 20 patients with Peyronie's disease aged 34 to 56 years using a GE Sonora Logic 500 MD US scanner with linear probes of 7.5 and 13 MHz. The microvascularization around the plaques was studied with color and power Doppler investigations before contrast agent administration and with combined color and power Doppler after contrast agent administration. We injected Levovist (300 mg/mL) and 10 micrograms prostglandin E1 (PGE1). Examinations were repeated after 2-4 months in the patients with evidence of microvascularization around the plaques. RESULTS: US demonstrated fibrocalcific plaques in all the patients. The microvascularization around the plaques was seen with color Doppler in 3 cases (15%), with power Doppler in 5 cases (25%) and with contrast-enhanced color and power Doppler in 7 cases (35%). At 2-4 months' follow-up, we observed slight plaque enlargement and worsened symptoms in 5 of 7 patients (71%) with evidence of some microvascularization around the plaque. CONCLUSIONS: The plaque presence allows to define the condition and the microvascularization provides information on its evolution. The disease activity can be distinguished into 3 stages which can be related to the painful symptoms. US exhibits a better cost/benefit ratio than contrast-enhanced MRI.

Adult↗

PubMed1992

[Artifacts in echo-Doppler and color-Doppler].

It is well known that artifacts can be observed during US examinations; the same is true also for Doppler and color-Doppler images of blood flow. Recognizing these artifacts is important to avoid image misinterpretations and, when possible, to overcome them by modifying either techniques or unit settings, or both. This work was aimed at presenting the several artifacts which can be observed during Doppler investigations, at classifying them, and trying to understand the physical and/or technical principles underlying their origin. Doppler and color-Doppler artifacts can be divided into four large groups: 1) artifacts regarding evaluation of the presence of flow; 2) artifacts regarding evaluation of the direction of flow; 3) artifacts regarding determination of the velocity of flow; 4) artifacts affecting spatial location, on the screen, of the examined vessel. Each of the above can cause severe diagnostic misinterpretations, if not correctly recognized and interpreted. It must be kept in mind that an accurate analysis of unit settings during scanning, and the meticulous evaluation of the obtained color images are of the utmost importance for the proper use of this valuable but difficult diagnostic technique.

Artifacts↗

PubMed1990

[Assessment of left ventricular diastolic function with color Doppler flow-comparison with pulsed Doppler and radionuclide angiography].

To determine the relations among color Doppler echocardiographic, pulsed Doppler echocardiographic and radionuclide angiographic fractions of left ventricular filling, 37 patients were studied using the three techniques. Favorable correlations of the filling fractions were found between color Doppler (flow area/left ventricular cavity area) and radionuclide angiography both during early diastole (r = 0.94) and atrial systole (r = 0.90). The above results were better than those obtained from pulsed Doppler (E area/Total, A area/Total) and radionuclide angiography: during early diastole (r = 0.78) and atrial systole (r = 0.76). Color Doppler can be used as a new method for assessing the pattern of left ventricular filling.

Adult↗

PubMed1990

[Estimation of systolic pulmonary artery pressure with continuous wave Doppler pressure gradient method: a simultaneous Doppler and catheter correlative study].

To estimate more precisely the systolic pulmonary artery pressure (PASP), continuous wave Doppler pressure gradient method and catheter measurement were performed simultaneously in 85 patients. There were 30 patients with tricuspid regurgitation (TR), 35 with ventricular septal defect (VSD), and 20 with patent ductus arterosus (PDA). For maximal transtricuspid pressure gradient (TRPG) determined by continuous wave Doppler and catheter determined PASP in TR group, the correlation coefficient (r) was as high as 0.99. For Doppler determined PASP (subtracting pressure gradient across PDA from systemic arterial pressure measured by cuff sphygmomanometer) and catheter determined PASP in PDA group, r was 0.95. Doppler determined PASP in VSD group (subtracting pressure gradient across VSD from systemic arterial pressure) also correlated well with catheter determined PASP (r = 0.97). This study demonstrates that continuous wave Doppler pressure gradient method can accurately estimate PASP in patients with TR, PDA, and VSD.

Adolescent↗

PubMed1995

[Comparative study of power Doppler and color Doppler in breast diseases].

In order to evaluate the interest of power doppler in breast studies, we studied 27 breast lesions in 22 patients. This series includes 8 malignant lesions, 11 benign lesions, and 8 enlarged lymph nodes. We used a Esaote Biomedica ultrasound machine with a 7 MHz transducer. We compared power doppler and pulsed doppler for every lesion. Power doppler was more sensitive in 3 out of 8 malignant tumors, 8 out of 11 benign lesions, and 5 out of 8 lymph nodes involvement. This study shows the value of power doppler in breast studies. The increased sensitivity, however, is balanced by a decreased specificity.

Breast Diseases↗

PubMed1995

Nature of flow acceleration into a finite-sized orifice: steady and pulsatile flow studies on the flow convergence region using simultaneous ultrasound Doppler flow mapping and laser Doppler velocimetry.

OBJECTIVES: This study investigated the proximal centerline flow convergence region simultaneously by both color Doppler and laser Doppler velocimetry. BACKGROUND: Although numerous investigations have been performed to test the flow convergence method, to our knowledge there has yet been no experimental study using reference standard velocimetric techniques to define precisely the hydrodynamic factors involved in the accelerating flow region during steady and pulsatile flow. METHODS: Using an in vitro model that allows velocity measurements by laser Doppler velocimetry with simultaneous comparison with color Doppler results, we studied the centerline flow acceleration region proximal to orifices of various sizes (0.08 to 2.0 cm2). RESULTS: Agreement between theory and experimental velocities was good for large flow rates through small orifices only, and only at distances > 1.2 cm from the orifice. Changing the orifice shape from circular to slitlike produced no significant changes in velocity profiles. Constraining the proximal side walls caused a significant increase in proximal velocities at distances > 0.7 cm for the largest orifice only (2.0 cm2). Calculated flow rates agreed well with actual flow rates, with functional dependence on proximal distance and orifice size. Velocity profiles for pulsatile flow were similar to steady state flow profiles and could be integrated to calculate stroke volumes, which followed actual flow volumes well, although with general overestimation (y = 1.22x + 0.164, r = 0.92), most likely due to the use of all available proximal velocities. CONCLUSIONS: The accelerating proximal flow region responds to several hydrodynamic factors that can affect flow quantitation using the flow convergence method in the clinical situation.

Blood Flow Velocity↗

PubMed1997

Acute effects of thromboxane dual blocker (KDI-792) on different portions of lower limb blood flow--a study using Doppler ultrasonography and laser Doppler flowmetry in type 2 diabetic patients.

The acute effects of a newly synthesized thromboxane dual blocker (KDI-792), a combined thromboxane synthase inhibitor and receptor antagonist, on lower limb circulation were examined using two-dimensional color and pulse Doppler ultrasonography and laser Doppler flowmetry. A randomized single-masked, placebo-controlled trial was performed on 36 type 2 diabetic patients with minimally impaired baseline flow. The anatomical cross-sectional area (CSA), maximum flow velocity (MFV) and flow volume index (FVI) in the right dorsal pedis artery (DPA) and right femoral artery (FA) were determined by Doppler ultrasonography before and 45 and 90 minutes after the administration of either 100 or 200 mg of KDI-792 to the dose groups or placebo to the control group. Periflux blood flow (PBF) in the right foot was determined simultaneously by laser Doppler flowmetry. Both CSA and MFV in the dose groups were significantly increased in both the FA and DPA. FVI was markedly increased from 21.4 +/- 3.7 to 68.3 +/- 26.8 in the DPA (M +/- SD, P < 0.01) and from 365.4 +/- 35.3 to 771.7 +/- 75.7 in the FA (P < 0.01) in the 200 mg dose group. In the 100 mg dose group, FVI was markedly increased from 20.0 +/- 8.7 to 68.3 +/- 26.8 (P < 0.01) in the DPA and from 372.5 +/- 130.0 to 677.5 +/- 187.8 (P < 0.01) in the FA. PBF was also increased in both dose groups (from 4.15 +/- 1.4 to 7.0 +/- 4.0 ml/min/100 g tissue in the 200 mg dose group, P < 0.01), whereas there were no significant changes in either measurement in the control group. There were no significant changes in pulse rate or blood pressure after administration in either the dosage group or the placebo group. These and previous findings indicate that a single administration of KDI-792 markedly increases lower limb blood flow and might have a more potent vasodilating effect than that of prostaglandin I2 derivatives.

Aged↗

PubMed1999

Accuracy of the main Doppler methods for evaluating the degree of carotid stenoses (continuous wave, pulsed wave, and color Doppler).

OBJECTIVE: To compare the accuracy of the main Doppler methods for quantifying the degree of carotid stenoses in 133 patients. METHOD: seven parameters were measured: maximum velocity (V.max) inside the stenosis (by pulsed wave [PW]), grade and index of spectral disturbance (STI) at the outlet of the stenosis (by PW and continuous wave [CW]), ratio of velocities I(IC/CC) in the internal and common carotid (by PW), and ratio of vessel cross-section and residual lumen area (%Color) inside the stenosis (color Doppler). The reference methods were the grades of spectral disturbance and the STI (by CW), already validated against endarterectomy specimens. CONCLUSION: For poststenosis measurements, a high correlation was found between the grades or STI measured by PW and CW (reference method). The measurement of these parameters was easier in PW mode. For intrastenotic velocity, the increase in V.max was not proportional to the degree of stenosis, and V.max showed large fluctuations for the same degree of stenosis. I(IC/CC) also showed large fluctuations for the same degree of stenosis. The correlation was poor for these two parameters, which could only be used for detecting two groups of stenosis: >75% or >90% in area. Color Doppler (conventional and power) routinely overestimated the degree of stenosis by 10%-15% but correlated better with the reference method and was more accurate and reproducible than V.max. A special procedure can be used to avoid this overestimation and improve the accuracy of the color Doppler.

Blood Flow Velocity↗

PubMed2001

Comparison of color-flow Doppler scanning, power Doppler scanning, and frequency shift for assessment of carotid artery stenosis.

OBJECTIVE: We investigated the accuracy of color-flow Doppler (CD) scanning, power Doppler (PD) scanning, and peak systolic Doppler frequency shift (PSF) in assessment of carotid artery stenosis with angiography used as gold standard, including the measurement techniques used in the North American Symptomatic Carotid Surgery Trial (NASCET) and the European Carotid Surgery Trial (ECST). METHODS: Fifty-eight consecutive patients diagnosed for carotid artery surgery underwent color-coded duplex sonography and angiography. The duplex examination included the assessment of PSF and the videotaping of sagittal images in CD and PD mode from the proximal common carotid artery to the distal internal carotid artery. Two experienced examiners performed the studies, but once one examiner had done the taping, the other examiner was allowed only to review the tape. Separately, each examiner reviewed the tapes and determined by cursor settings each stenosis according to NASCET and ECST. For interobserver agreement kappa statistic was used. To compare with angiography (degree of stenosis 40%, 50%, 60%, 70%, and 80%) sensitivity, specificity, positive and negative predictive values, and overall accuracy were calculated. PSF cut-off frequencies were based on receiver operator curve analysis. RESULTS: Because interobserver agreement in CD and PD was good (chance-corrected kappa > 0.6), further analysis used the between-observer mean value for each stenosis. With the NASCET measurement technique, accuracy of Doppler techniques to distinguish a 50% stenosis was 89% for PSF, 91% for CD, and 93% for PD; for a 70% stenosis it was 83% for PSF, 84% for CD, and 81% for PD. With the ECST measurement technique, accuracy to distinguish a 70% stenosis was 86% for PSF, 88% for CD, and 86% for PD; for an 80% stenosis it was 87% for PSF, 87% for CD, and 77% for PD. CONCLUSION: CD and PD carotid artery stenosis measurements are highly reproducible, and in our hands provided accuracy equal to PSF.

Aged↗

PubMed1996

Sonographic assessment of carotid artery stenosis. Comparison of power Doppler imaging and color Doppler flow imaging.

BACKGROUND AND PURPOSE: Power Doppler imaging (PDI) is a new ultrasound technique that, in contrast to color Doppler flow imaging (CDFI), generates intravascular color signals from the reflected echo amplitude depending mainly on the density of red blood cells. We evaluated the diagnostic significance of PDI compared with CDFI for the measurement of carotid stenosis and characterization of plaque surface. METHODS: In 25 internal carotid artery stenoses, reduction of the intrastenotic lumen contrasted by blood density signals and color Doppler signals on longitudinal and transverse views was assessed for correlative evaluation. In addition, the peak systolic flow velocity of the Doppler spectrum was correlated with PDI and CDFI measurements. RESULTS: PDI provided good visualization of the residual lumen in all stenoses, whereas displays on CDFI were inadequate in two calcified plaques. PDI revealed two ulcerative stenoses classified as smooth on CDFI. The correlation between PDI and CDFI was high for measurement of area stenosis (r = .93) and moderate for diameter stenosis (r = .73). Similarly, cross-sectional reduction on both imaging methods correlated more significantly with peak systolic flow velocity than diameter reduction. CONCLUSIONS: This pilot study suggests that PDI provides additional information for luminal measurement and characterization of plaque surface in complicated high-grade carotid stenosis. Because of the absent visualization of hemodynamics, PDI should be used in combination with CDFI.

Aged↗

PubMed1992

Doppler and color Doppler ultrasonography in renal transplants: chronic rejection.

Although Doppler and color Doppler ultrasonography has been used extensively to examine acute changes in renal allograft function, there have been few reports on the role of Doppler ultrasonography in the assessment of chronic rejection. In those studies that have addressed chronic rejection, there is agreement that changes in renal function are not accompanied by consistent changes in flow wave-form shape. The pathology of chronic rejection may be very different from the changes seen in acute rejection and its onset is usually gradual. Some authors have suggested that the decline in function is accompanied by lower Doppler frequency shifts (corresponding to lower velocities) in intra-renal arteries. In a preliminary study comparing grafts with normal renal function and with biopsy-proven chronic rejection, it has been shown that for grafts with chronic rejection, observed intra-renal velocities are lower, especially at segmental and interlobar levels. This may be a more reliable reflection of reduced renal blood flow in chronic rejection than conventional Doppler ultrasound analysis of flow waveform shape. However, the diagnostic use of changes to intra-renal flow velocities in chronic rejection is currently very limited.

Graft Rejection↗