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At least 217 records · Page 12Linked to original sources

PubMed2005

Comparison of tissue Doppler dynamics to Doppler flow in evaluating left atrial appendage function by transesophageal echocardiography.

Tissue Doppler imaging (TDI) patterns from the left atrial appendage (LAA) were evaluated by transesophageal echocardiography. Reproducible, characteristic triphasic or biphasic tissue velocities similar to Doppler flow of the LAA were obtained. Patient peak TDI velocities correlated well with flow and were measurable in atrial fibrillation. Patients with an embolic cerebrovascular accident and in sinus rhythm had higher tissue TDI velocities from the LAA compared with patients without an event, and the groups had similar flow velocities. Hence, Doppler tissue contraction dynamics determined by TDI may complement flow velocities in evaluating LAA function for risk assessment of thromboembolism.

Adult↗

PubMed2003

Quantification of ovarian Doppler signal in hyperresponders during in vitro fertilization treatment using three-dimensional power Doppler ultrasonography.

To test the hypothesis that the increased 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, we undertook this prospective comparative clinical study using three-dimensional (3-D) power Doppler ultrasound (US). The 3-D power Doppler ultrasonographic indexes were used to quantify ovarian stromal blood flow and vascularization in hyperresponders. A total of 58 patients undergoing an IVF cycle were recruited and divided into two groups, a hyperresponder group (n = 23) (peak estradiol > 3000 pg/mL or >/= 15 oocytes retrieved) and normal responders (n = 35), based on their response to a standard down-regulation protocol for controlled ovarian stimulation. During ovarian stimulation, on the day of human chorionic gonadotropin (HCG) administration, patients underwent hormonal (serum E2), ovarian volume and 3-D power Doppler (ovarian stroma flow) evaluation. The serum estradiol levels on the day of HCG administration, the number of oocytes retrieved and the ovarian volume were significantly higher in the hyperresponders than in the normal groups. The vascularization flow index (VFI), flow index (FI), and vascularization index (VI), were significantly higher (p < 0.05) in the hyperresponders (1.18 +/- 0.60, 50.23 +/- 2.81 and 2.27 +/- 1.08, respectively), compared to the women with a normal response (0.63 +/- 0.61, 43.19 +/- 7.81 and 1.25 +/- 1.18, respectively). Our study may help to explain the excessive response during gonadotropin administration in the hyperresponsive women.

Adult↗

PubMed2003

Doppler pressure field deduced from the Doppler velocity field in an observation plane in a fluid.

A new method is developed for a nondisturbing and quantitative measurement of the pressure at an arbitrary point in a flowing fluid in three-dimensional (3-D) space. In this method, after measuring the velocity field in the observation plane (scanning plane) using the pulsed Doppler technique, the velocity component orthogonal to the Doppler velocity is deduced, taking the law of conservation of mass (the equation of continuity) into consideration. Then, the pressure, "Doppler pressure," is calculated from the acceleration. It is expected that, when this method is applied to cardiology in clinical medicine, it will be very useful as a clinical diagnostic tool for the practical analysis and estimation of hemodynamics in the blood flow in the heart chambers, because the pressure field can be displayed as a 2-D contour.

Adult↗

PubMed1999

3-D power Doppler cerebral angiography in neonates and young infants: comparison with 2-D power Doppler angiography.

The aims of this study were to evaluate the ability of 3-dimensional (3-D) power Doppler angiography (3DPDA) to depict the intracranial vasculature in infants, to compare with 2-D power Doppler ultrasonography (2DPDU), and to explore the potential clinical applications of this procedure in young infants with brain disorders. We performed 3DPDA in 27 infants. 2DPDU were completed in both sagittal and coronal directions in 12 of these patients. In the other 15, only right sagittal plane images were available for comparison. Using a grading system and with only vessels with more than half of the length demonstrated included for comparison, we compared the Doppler signals of major vessels. 3DPDA could have good visualization in more than 60% of the internal carotid artery, ophthalmic artery, pericallosal artery, callosomarginal artery, internal cerebral vein, vein of Galen, and straight sinus in the sagittal plane. 3DPDA also could have good demonstration in about 50% of basilar artery in coronal plane, and posterior communicating artery, posterior cerebral artery, and lenticulostriate artery in sagittal plane. 3DPDA was better than 2DPDU in demonstrating all the major intracranial vessels in different planes, except the anterior communicating artery. In the anterior communicating artery, neither can demonstrate more than 30%.

Brain Diseases↗

PubMed2000

Doppler tissue imaging in congestive heart failure patients due to diastolic or systolic dysfunction: a comparison with Doppler echocardiography and the atrio-ventricular plane displacement technique.

BACKGROUND: Doppler tissue imaging (DTI) is an echocardiographic technique by which regional contractility, relaxation properties and time intervals are obtained easily. DTI has been reported to be relatively pre-load independent and could, in comparison with the commonly used mitral pulse wave Doppler (MPWD) method, be of clinical interest for identification of patients with diastolic dysfunction. The atrio-ventricular plane displacement (AVPD) method is an established technique to assess left ventricular systolic function. AIMS: To determine the pulsed Doppler DTI-pattern in patients with heart failure and to examine whether it has a similar capacity as MPWD and AVPD to diagnose diastolic dysfunction. METHODS: We studied 15 controls without congestive heart failure (CHF), 15 patients with diastolic (EF>45%+CHF) and 15 patients with systolic (EF<35%+CHF) left ventricular dysfunction and CHF. RESULTS: The DTI maximal velocities during systole (s), early filling wave (e) and atrial filling wave (a), decrease with reduced left ventricular ejection fraction, r=0.75, r=0.56 and r=0.66 (P<0.001) and regional isovolumetric contraction and intraventricular relaxation time measured by DTI are prolonged, r=0.59 and r=0.73, respectively (P<0.001). The 15 patients with diastolic heart failure were identified by MPWD or DTI but only 11 by AVPD with 8, 10 and 9 false-positive, respectively (P<0.01, P<0.05 and NS). CONCLUSIONS: Regional DTI show a consistent pattern in patients with left ventricular dysfunction and heart failure. Regional DTI has similar accuracy as MPWD in identifying diastolic heart failure patients and is superior to the AVPD technique. DTI may be a useful diagnostic tool in diastolic heart failure patients.

Aged↗

PubMed2001

Comparison of myocardial tissue Doppler with transmitral flow Doppler in left ventricular hypertrophy.

We sought to determine the most useful echocardiographic measurements for assessment of diastolic function in patients with left ventricular hypertrophy (LVH) and normal systolic function. We compared myocardial Doppler velocities of the basal inferoposterior wall with mitral inflow pulsed wave Doppler velocities in 11 healthy volunteers (age, 36 +/- 6 years), 25 patients (age, 64 +/- 14 years) without LVH, and 37 patients (age, 67 +/- 14 years) with LVH and otherwise normal echocardiograms. The discriminatory measurements were myocardial A-wave duration (120 +/- 18 versus 98 +/- 20 and 92 +/- 12 ms, P <.0001), myocardial isovolumetric relaxation time (124 +/- 45 versus 95 +/- 48 and 78 +/- 25 ms, P =.0035), mitral A-wave velocity (0.98 +/- 0.37 versus 0.73 +/- 0.28 m/s and 0.61 +/- 0.22 m/s, P =.009), and mitral E-wave deceleration time (257 +/- 93 versus 201 +/- 85 ms and 184 +/- 83 ms, P =.015), which were significantly increased, and myocardial E-wave velocity (0.84 +/- 0.04 m/s versus 0.13 +/- 0.03 m/s and 0.14 +/- 0.03 m/s, P <.0001), which was significantly decreased, in patients with LVH compared with patients without LVH and normal volunteers, respectively. Left ventricular posterior wall thickness correlated with myocardial isovolumetric relaxation time (r = 0.52, P <.0001) and myocardial A-wave duration (r = 0.59, P <.0001), negatively with myocardial E wave (r = -0.43, P <.0001), and showed no correlation with mitral inflow parameters except mitral inflow A wave (r = 0.43, P =.002). On multivariate analysis using these variables, myocardial isovolumetric relaxation time (P =.0014) and A-wave duration (P =.001) were the only 2 variables that correlated with posterior wall thickness (multiple R = 0.71). In the presence of LVH and preserved left ventricular systolic function, myocardial relaxation time and velocities are more sensitive than mitral Doppler inflow parameters in detecting abnormal left ventricular relaxation.

Adult↗

PubMed2001

Estimation of left ventricular end-diastolic pressure by color M-mode Doppler echocardiography and tissue Doppler imaging.

OBJECTIVES: The aim of this study was to estimate left ventricular end-diastolic pressure (LVEDP) noninvasively by tissue Doppler imaging and color M-mode echocardiography. MATERIAL AND METHODS: We studied 3 groups of patients who were proven by angiography to be free of significant coronary artery lesions (<40% stenosis) with an LVEDP < 10 mm Hg (group A: n = 24; 16 men, 18 women; mean age +/- SD = 55 +/- 13 years), an LVEDP of 10 to 15 mm Hg (group B: n = 21; 17 men, 4 women; mean age 56 +/- 11 years), or an LVEDP > 15 mm Hg (group C: n = 35; 20 men, 15 women; mean age 58 +/- 9 years). Tissue Doppler imaging of the lateral mitral annulus and color M-mode imaging of the mitral valve in the apical 4-chamber view were obtained with an echocardiographic system. Early and late diastolic velocities (Em and Am, respectively), Em deceleration time (EmDT), Am time (Am-t), and mitral propagation velocity time delay (VpDT) were measured in each patient. RESULTS: In group A, sensitivity and specificity for EmDT < or = 100 ms, Am-t < or = 90 ms, Em/Am > or = 1, and VpDT < or = 45 ms were found to be 0.57 and 0.89, 0.66 and 0.88, 0.86 and 0.92, and 0.73 and 0.89, respectively. In group B, sensitivity and specificity for EmDT 100 to 120 ms, Am-t 90 to 110 ms, Em/Am 1 to 0.5, and VpDT 45 to 60 ms were found to be 0.57 and 0.84, 0.69 and 0.82, 0.66 and 0.75, and 0.55 and 0.83, respectively. In group C, sensitivity and specificity for EmDT > 120 ms, Am-t > 110 ms, Em/Am < 0.5, and VpDT > 60 ms were found to be 0.88 and 0.81, 0.71 and 0.80, 0.86 and 0.72, and 0.78 and 0.86, respectively. CONCLUSION: The EmDT, Am-t, Em/Am, and VpDT measurements obtained noninvasively by left ventricular tissue Doppler imaging and mitral flow propagation velocity were found to be useful in the estimation of LVEDP.

Adult↗

PubMed2002

Quantification of Doppler signal in polycystic ovary syndrome using three-dimensional power Doppler ultrasonography: a possible new marker for diagnosis.

BACKGROUND: Differences in the ovarian stromal blood flow of women embarking on an IVF treatment, as assessed on day 2 or 3 of the menstrual cycle, using three-dimensional (3D) power Doppler ultrasonography to quantify the blood flow and vascularization, were compared. METHODS: The women were divided into two groups: group 1, 54 women with regular, ovulatory menstrual cycles and normal ovaries on ultrasound scan; and group 2, 25 women with polycystic ovary syndrome (PCOS). RESULTS: The quantification of Doppler signal in the ovarian stroma appeared to be greater in the PCOS group compared with the normal group. The mean of ovarian volume was significantly higher (P < 0.05) in women with PCOS compared with the normal ovaries. The vascularization flow index (VFI), flow index (FI), and vascularization index (VI), were significantly higher (P < 0.05) in the women with PCOS compared with the women with normal ovaries. CONCLUSIONS: This observation may help to explain the excessive response often seen during gonadotrophin administration in women with PCOS. We believe that a quantification study of the vascular flow, including the VI, FI, and VFI of the entire ovarian stroma using 3D power Doppler, is more accurate than the previously reported quantification analysis using 2D imaging, and may be a new parameter to assist in the ultrasound diagnosis of PCOS.

Adult↗

PubMed2005

Evaluation of left ventricular function in cardiomyopathic mice by tissue Doppler and color M-mode Doppler echocardiography.

Tissue Doppler imaging (TDI) and color M-mode Doppler flow propagation velocity (Vp) are used to assess cardiac function in humans, but the feasibility and applicability of these measurements to murine cardiomyopathic models of heart failure remain unclear. Left ventricular (LV) function was measured by TDI and Vp among mice exhibiting severe dilated cardiomyopathy (TOT), pressure-overload hypertrophy (TAC), and normal controls (NTG). Transmitral flow pattern in TACs and TOTs showed a restrictive filling pattern, but early diastolic mitral annulus velocity was comparable among the three studied groups. Propagation velocity in an anesthetized state was comparable in all three groups. However, while Vp increased in all three groups in the conscious state, the increase in NTGs was statistically greater than in TACs and TOTs. Collectively, results indicate that color M-mode Doppler echocardiography can be used to assess LV function in mice. Furthermore, Vp is depressed by anesthesia, a complication that can lead to misinterpretation of LV function in normal hearts.

Anesthetics, Inhalation↗

PubMed2004

Tissue Doppler imaging and echo-Doppler findings associated with a mitral valve stenosis with an immobile posterior valve leaflet in a bull terrier.

A mitral valve stenosis was diagnosed in a 2-year-old female Bull Terrier by use of two-dimensional (2-D) and M-mode echocardiography, colour-flow imaging and spectral Doppler examinations. Tissue Doppler Imaging was also performed to assess the segmental radial myocardial motion. The mitral valve stenosis was characterized by a decreased mitral orifice area/left ventricle area ratio (0.14), an increased early diastolic flow velocity (E wave = 1.9 m/s), a prolonged pressure half-time (106 ms) and a decreased E-F slope (4.5 cm/s) on pulsed-wave Doppler examination. This mitral stenosis was associated with an immobile posterior leaflet, as seen on 2-D and M-mode echocardiography. Immobility of the posterior mitral leaflet is considered to be a rare finding in humans and, to our knowledge, has not been precisely documented in dogs with mitral valve stenosis.

Animals↗

PubMedDate not supplied

Color flow Doppler imaging and Doppler spectral analysis of the brain of neonatal dogs.

Doppler ultrasonography was performed on the cerebral arteries of 19 neonatal dogs. Vascular structures were identified using anatomic preparations of brains pre-injected with a radiopaque silicone rubber product and cleared using a modified tissue clearing technique. Brain sections were subsequently radiographed or examined under a stereomicroscope. Color flow Doppler imaging was used to facilitate positioning of the Doppler calipers for measurement of peak systolic velocity, minimum diastolic velocity, and resistance index. Blood flow velocities in the internal carotid and middle cerebral arteries were lower when measured in transverse images than in sagittal images. The rostral cerebral arteries could be measured using either plane but values obtained from different locations or using different methods of measurement were statistically different. Blood flow velocities generally increased during the first month after birth. Arterial signals were diphasic with flow throughout diastole. Resistance indices most often were between 0.6 and 0.7 and did not exceed 0.86.

Animals↗

PubMedDate not supplied

Evaluation of cardiovascular flow characteristics in the 129Sv mouse fetus using color-Doppler-guided spectral Doppler ultrasound.

The purpose of this study was to evaluate color- and spectral Doppler ultrasound in the establishment of normal functional cardiovascular development features in the mouse fetus. Mouse fetuses (129Sv strain) were studied in utero between embryonic day (EDs) 9.5 and 19.5. Time-velocity curves were derived from Doppler interrogation of the aorta and umbilical artery. The sample volume was accurately placed on the vessels of interest based on color-Doppler images. From these curves, the following parameters were obtained: heart rate (HR), acceleration time (AT), and deceleration time (DT). HR increased between EDs 9.5 and 19.5 from 102.9 to 303.2 b.p.m. For the other parameters, the most significant change observed was the increase of DT in the umbilical artery at the end of pregnancy, corresponding to the appearance of a diastolic flow. We report the use of a commercially available, clinical, ultrasound unit to obtain quantitative data on the cardiovascular development in the mouse fetus. These results may be useful for the recognition of in utero cardiovascular dysfunction in transgenic or knock-out fetus.

Animals↗

PubMed1992

Influence of the Coanda effect on color Doppler jet area and color encoding. In vitro studies using color Doppler flow mapping.

We studied surface adherence and its effects on color Doppler jet areas and color encoding in an in vitro model with a noncompliant receiving chamber into which a steady flow jet was directed parallel to either a straight or a curved surface adjacent to and 4 mm away from the inflow orifice (1.50 mm2) with the control condition being a free jet matched for flow rates and driving pressures. Jets were imaged perpendicular to the plane of the surface, the plane in which most clinical images of jet-surface interactions are obtained. Ten different flow rates ranging from 0.13 to 0.30 l/min were used. Surface-adherent jet areas were smaller than control jets for every driving pressure-volume combination (paired t test, p less than 0.01). Computer analysis of color Doppler images showed more green and blue (reverse flow) pixels on the surface side of the adherent jets than the control jets (p less than 0.05), suggesting that viscous energy loss and flow deceleration and reversal play a role in the jet-surface interaction. Analysis of variance demonstrated that linear regression slopes of flow rate versus jet area for surface jets were lower (slopes, 11-21 cm2/l/min; r = 0.95-0.97) than those for the control (slope, 33 cm2/l/min; r = 0.97) (p less than 0.0001). Surface adherence (Coanda effect) influences jet size and color encoding, causing smaller color Doppler jet areas and greater variance and reverse velocity encoding.

Coronary Circulation↗

PubMed1991

An efficient algorithm to remove low frequency Doppler signals in digital Doppler systems.

In color flow imaging, a high flow map rate in combination with a reasonable width of the map and good velocity resolution is essential to properly appreciate the time-dependent phenomena. The velocity resolution depends on the length of the signal segment considered in combination with the settling time of the high pass filter used to eliminate transients and low frequency artifacts. The latter can be reduced by appropriate processing. This paper presents an algorithm to suppress low frequency Doppler signals effectively and efficiently, while all the data points within the segment considered contribute equally to the average Doppler frequency computed. The algorithm is applied to computer generated Doppler signals to evaluate their time and frequency behavior. It is concluded that the proposed scheme functions adequately under various signal conditions.

Algorithms↗

PubMed1999

Assessment of the temporal relationship between left ventricular relaxation and filling during early diastole using pulsed Doppler echocardiography and tissue Doppler imaging.

The study investigated the temporal relationship between left ventricular (LV) relaxation and filling during early diastole. The transmitral flow (TMF) velocity by pulsed Doppler echocardiography and LV wall motion velocity by pulsed tissue Doppler imaging (TDI) were evaluated in 57 patients with various heart diseases and 33 normal controls. The patients were classified into 2 groups according to the ratio of the peak early diastolic to atrial systolic TMF velocity (E/A): (1) the high A group included 44 patients with an E/A < or = 1, and (2) the pseudonormalization group included 13 patients with an E/A > 1. The isovolumic relaxation time (IRT) from the aortic component of the second heart sound (IIA) to the onset of the E wave of the TMF was measured. The peak early diastolic velocity of the LV posterior wall (Ew) and time from the IIA to the onset of the early diastolic wave (IIA-Ewo) were determined from the LV wall motion velocity assessed by pulsed TDI. The Ew was lower in the pseudonormalization and high A groups than in the control group. The IIA-Ewo was significantly longer in the pseudonormalization and high A groups than in the control group. The time constant of the LV pressure decay at isovolumic diastole (tau) correlated negatively with the Ew, and correlated positively with the IIA-Ewo in all groups. The IIA-Ewo was equal to or shorter than the IRT in control subjects, and was longer than the IRT in patients in the pseudonormalization group. In conclusion, the temporal relationship between LV relaxation and filling during early diastole varied according to the subjects' hemodynamic status. Analysis of TMF by pulsed Doppler echocardiography and LV wall motion velocity by pulsed TDI was useful for detailed evaluation of early diastolic LV hemodynamics.

Blood Flow Velocity↗

PubMed2000

Assessment of coronary flow reserve with transthoracic Doppler echocardiography: comparison with intracoronary Doppler method.

To evaluate the feasibility and usefulness of transthoracic Doppler echocardiography (TTDE) as a non-invasive method in recording distal anterior descending (LAD) coronary flow velocity, we compared coronary flow reserve (CFR) measured by TTDE with measurements by intracoronary Doppler wire (ICDW). Twenty-one patients without LAD stenosis were studied. ICDW performed at baseline and after intracoronary injection of 18 microg adenosine. TTDE was performed at baseline and after intravenous adenosine (140 microg/kgmin for 2 min). Adequate Doppler recordings of coronary flow velocities during systole were obtained in 14 of 21 study patients (67%) and during diastole in 17 (81%) patients. Baseline and hyperemic peak diastolic flow velocities measured by TTDE were significantly smaller than those obtained by ICDW (p<0.05). However, diminishing trends of diastolic and systolic velocity ratio after hyperemia were similarly observed in both methods. CFR obtained by TTDE (3.0+/-0.5), was higher than the value calculated by ICDW (2.5+/-0.4). There were significant correlations between the values obtained by the two methods (r=0.72, p<0.01). It is concluded that TTDE is a feasible method in measuring coronary flow velocity and appears to be a promising non-invasive method in evaluating CFR.

Adult↗

PubMed1999

Doppler Monte Carlo simulations of light scattering in tissue to support laser-Doppler perfusion measurements.

Doppler Monte Carlo (DMC) simulations of the transport of light through turbid media, e.g., tissue, can be used to predict or to interpret measurements of the blood perfusion of tissue by laser-Doppler perfusion flowmetry. We describe the physical and mathematical background of Doppler Monte Carlo calculations, and present some comparisons with measurements, performed with experimental flow models, built to mimic skin tissue characteristics and for the calibration of perfusion instruments,which are important goals of the Biomed-I concerted action. The measurements deal with coherence effects.

Calibration↗

PubMed2000

Reference ranges and standard percentile-curves for the Doppler indices RI and S/D ratio of the fetal middle cerebral artery. Color Doppler measurements in a perinatal centre.

PURPOSE: To perform reference ranges and standard percentile-curves for the Doppler indices resistance index (RI) and systolic/diastolic (S/D) ratio of the fetal middle cerebral artery, periodical color doppler sonographic measurements of 70 pregnant women in the 3rd trimester of pregnancy were done. METHODS: 600 Doppler flow measurements of the fetal middle cerebral artery between 28 and 40 weeks of gestation were performed. The patients had no previous obstetric complications, no apparent medical problems and no complications in pregnancy and labor. Percentiles curves were performed for the RI and the S/D ratio from the 10th percentile up to the 90th percentile. RESULTS: In the 3rd trimester of pregnancy fetal cerebral circulation shows an increase of the diastolic component and simultaneous decrease in cerebral resistance. The average S/D ratio in week 29 is 8.0, in week 34 6.0 and in the 40th week 3.5. The RI decrement is from 0.88 to 0.67. Other groups demonstrated similar ranges however absolute data are different. CONCLUSION: The increase in the diastolic component in the middle cerebral artery of the last third of the pregnancy demands reference ranges by using percentile curves. Knowledge of the reference range helps to discriminate between a normal fetal situation and disease. Because of different absolute ranges in the literature each perinatal centre should develop their own data.

Adolescent↗