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At least 163 records · Page 9Linked to original sources

PubMed1993

A study of blood supply of liver tumors using duplex Doppler ultrasound and color Doppler flow imaging.

With the use of duplex Doppler ultrasound and color Doppler flow imaging (CDFI), the characteristics of blood supply in neoplasma were studied in 51 cases of 60 liver tumors, and compared with the results of surgery, pathological examination and hepatic arterial angiography. The result showed that: 1. Doppler blood flow signals could be detected in all hepatic carcinomas, and in 10 cases of 18 hemangiomas, significant difference was observed (P < 0.001); 2. Doppler blood flow spectra showed pulsatile pattern in 41 of 42 hepatic carcinomas, and in 6 of 10 hemangiomas (P < 0.01); and 3. the peak flow velocity was obviously lower in hemangioma group than in hepatic carcinoma group (20.34 +/- 23.93 vs 64.74 +/- 30.18 cm, P < 0.001). The characteristics of CDFI show that hemangiomas and hepatocellular carcinomas are different. It can, therefore, be concluded that the blood supply of hepatic carcinomas mainly comes from hepatic arterial system, and is of value in duplex Doppler ultrasound and CDFI.

Adult↗

PubMed1984

Doppler echocardiographic features of coronary arteriovenous fistula. Complementary roles of cross sectional echocardiography and the Doppler technique.

The Doppler echocardiographic features of coronary arteriovenous fistula were investigated in eight patients with left or right coronary arteriovenous fistulas who had a continuous heart murmur in the upper precordial area and whose diagnoses were confirmed by coronary angiography. In four patients the dilated lumen of the coronary arteriovenous fistula was visualised by cross sectional echocardiography. Of these, three showed abnormal unidirectional continuous flow signals with broad velocity spectra in the fistula. Abnormal, powerful, unidirectional or bidirectional continuous Doppler signals were detected in part of the pulmonary artery in two of the eight patients, in part of the right ventricle in two, and in part of the right atrium in one; these signals were interpreted as indicating shunt flow. Although the opening of the fistula was difficult to visualise by cross sectional echocardiography, the pulsed Doppler technique helped identify the site in patients with dilatation of the coronary artery. In the remaining three patients with a small shunt no abnormal findings were obtained with cross sectional echocardiography or the Doppler technique. The size of the fistula below which no abnormal findings may be obtained by Doppler echocardiography still needs to be determined.

Adult↗

PubMed1984

The superiority of combined continuous wave Doppler examination over periorbital Doppler for the detection of extracranial carotid disease.

Non-invasive examination of 431 vessels in 333 patients with cerebrovascular disease in all stages was performed in order to compare the reliability of the periorbital Doppler test alone and together with the more difficult insonation of the carotid arteries in the neck (combined Doppler). These findings were compared with those of subsequent arteriography. Extracranial obstructive (greater than 50%) carotid disease was detected with 100% sensitivity by the combined Doppler, but with only 48% sensitivity by the periorbital indirect test. The specific ability of both methods to identify non-stenotic carotid arteries (less than 50%) was similar at about 98%. Only the combined Doppler examination reliably differentiated various degrees of obstruction, comparable to that obtained with arteriography. Non-obstructive plaques could not be detected or excluded by either Doppler test. More refined methods will be necessary for their evaluation.

Adolescent↗

PubMed1994

Power Doppler US: a potentially useful alternative to mean frequency-based color Doppler US.

PURPOSE: The authors present a preliminary report to demonstrate a new color Doppler (CD) ultrasonography (US) technique called power Doppler (PD), which displays the total integrated Doppler power in color, and to compare PD with CD imaging, which generally displays an estimate of the mean Doppler frequency shift. MATERIALS AND METHODS: Two standard commercial US scanners that encode the integrated power in the Doppler signal in color were used to demonstrate PD. A standard nonflow-containing US phantom, a normal right kidney, and a torsive and normal contralateral testis were scanned in the power mode. In the phantom and kidney, results with CD and PD were directly compared. RESULTS: PD does not alias, is relatively angle independent, and displays background noise in a way that increases the usable dynamic range of a US scanner. This extended dynamic range should increase machine sensitivity and may demonstrate increased flow in certain circumstances. CONCLUSION: PD is a new CD imaging imaging mode that might be superior to CD in some cases.

Humans↗

PubMed1987

[Diagnostic contribution of ultrasonic diagnosis coupled with pulsed Doppler combined with continuous Doppler to the exploration of the vertebral arteries of atherosclerotic patients. Preliminary report].

Velocimetric exploration by continuous emission Doppler is still essential for non-invasive evaluation of vertebral circulation but it does not provide morphologic data. Results were compared of exploration with combined continuous emission Doppler and a Duplex examination (sectorial scanning ultrasound imaging coupled with pulsed emission Doppler) and data from arteriography of 186 vertebral arteries in patients, mean age 57 years, admitted for exploration of a cerebral ischemic accident or a cervical murmur. The Duplex examination allowed identification of proximal segment (VI) in 98% of permeable vertebral arteries. The ostium of the vertebral artery was more difficult to visualize because of possible tortuosities, of sometimes a too posterior or intrathoracic localization or of a short neck. Nevertheless the vertebral ostium was identified in 78% of cases on the right and 48% on the left. The Duplex examination demonstrated sensitivity of 72% and specificity of 98% for detection of proximal stenosis of vertebral artery, and its sensitivity was therefore twice as sensitive as continuous emission Doppler for detection of stenoses of less than 50%. The Duplex examination should complete data from continuous emission Doppler by providing an evaluation of vertebral artery diameter and information on presence and characters of an elongation or stenosis. In this way, 9 atheromatous plaques not identified on arteriography were detected by ultrasound imaging. Similarly, the Duplex examination is particularly useful for identification of a hypoplastic vertebral artery, to distinguish the specific lesions of the subclavian artery from those extending onto vertebral ostium, and to characterize ostial lesions when these are accessible to examination.(ABSTRACT TRUNCATED AT 250 WORDS)

Basilar Artery↗

PubMed1986

[Measurement by Doppler echocardiography of the pulmonary arterial pressure in children with ductus arteriosus. Simultaneous Doppler and hemodynamic study].

The aim of this study was to evaluate Doppler echocardiography in the non invasive assessment of pulmonary artery pressures in children with patent ductus arteriosus. Systolic pulmonary artery pressure was measured simultaneously at cardiac catheterisation and by pulsed Doppler in 11 children (mean age 1.8 +/- 2 years) with patent ductus arteriosus alone (6 cases) or associated with a malformation of the heart or great arteries (5 cases). Doppler assessment of systolic pulmonary artery pressure was performed by subtracting the value of the maximal pressure gradient between the aorta and pulmonary artery from the systolic systemic pressure measured simultaneously by sphygmomanometry. The maximal pressure gradient between the aorta and pulmonary artery was calculated using the modified Bernouilli formula and the maximal velocity (v) of the shunt flow (gradient = 4 v2). Ductal flow was recorded from the suprasternal approach by direct interrogation of the patent ductus visualised by 2D echocardiography. The systolic pulmonary arterial pressure measured by catheterisation ranged from 21 to 82 mmHg (mean 58 +/- 21 mm Hg) and by pulsed Doppler from 20 to 89 mm Hg (mean 56 +/- 24 mm Hg) (correlation r = 0.94). This study illustrates the value of Doppler echocardiography in the assessment of systolic pulmonary artery pressures in children with patent ductus arteriosus.

Blood Pressure Determination↗

PubMed1987

[Doppler measurement of transvalvular gradients. Simultaneous Doppler-catheterization recordings on 78 patients].

Several studies have demonstrated the value of Doppler ultrasound as a means of measuring gradients across cardiac valves. However, in view of sudden variations in cardiac output gradients should be measured simultaneously by Doppler and catheterization in order to validate the former method and determine its accuracy. We conducted a prospective study with simultaneous recordings in 78 patients with aortic valve stenosis (33) or mitral valve stenosis (19) or cardiac valve prosthesis (26). Mean age of the patients was 55 +/- 14 years, and 50% of them were male. Subjects with pure or predominant regurgitation were excluded from the study. In the whole of the population studied, correlation between Doppler ultrasound and haemodynamics was very good with r = 0.98, p less than 0.001 for maximum gradient and r = 0.96, p less than 0.001 for mean gradient. The perfect simultaneity of the haemodynamic and ultrasonic recordings was confirmed by comparing the duration of gradients measured by the two methods (r = 0.996, p less than 0.001). There also was very close correlation between ultrasounds and catheter in patients with mitral stenosis (maximum gradient r = 0.98, p less than 0.001; mean gradient r = 0.97, p less than 0.001). Mean Doppler-catheter differences were not significant, and no underestimation by Doppler reached or exceeded 5 mmHg. Correlations were also satisfactory in patients with aortic stenosis (maximum gradient r = 0.97, p less than 0.01; mean gradient r = 0.90, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Stenosis↗

PubMed2001

Comparison of transcranial color Doppler imaging (TCDI) and transcranial Doppler (TCD) in children with sickle-cell anemia.

BACKGROUND: Transcranial Doppler (TCD) has been demonstrated to identify those at highest risk of stroke among children with sickle-cell disease. Based on a randomized clinical trial [Stroke Prevention in Sickle-Cell Anemia Trial (STOP)], which ended in 1997, the National Heart Lung and Blood Division of NIH has recommended TCD screening and chronic blood transfusion based on Nicolet TC 2000 dedicated Doppler (TCD). Studies performed using TCD imaging modalities need to be correlated to that used in the clinical trial to provide information for treatment decisions when screening with TCDI. OBJECTIVE: To correlate transcranial arterial time-averaged mean velocities obtained from an Acuson Transcranial Doppler Imaging to those obtained using the TCD as the gold standard for treatment decisions based on STOP. MATERIALS AND METHODS: A total of 29 children with sickle-cell disease, age 3-16 years, were studied at one of two scanning sessions using both techniques and a scanning protocol based on that used in STOP performed and read independently. The average difference in the measured velocities for each arterial segment was tested to determine difference from zero. Differences were compared before and after modifications to the TCDI technique were made to mimic the STOP protocol more closely. RESULTS: TCDI velocities were generally lower than TCD velocities for the same segment, but the difference was reduced (from 15 % to 10% for the middle cerebral artery) by modifications to the TCDI protocol. CONCLUSIONS: Measurements using the Acuson system are modestly lower than those obtained with dedicated Doppler using the Nicolet TCD.

Adolescent↗

PubMed2005

Use of tissue Doppler and its comparison with other conventional Doppler techniques in the assessment of diastolic functions in patients with active rheumatoid arthritis.

OBJECTIVE: This study aims to assess left ventricular diastolic functions with tissue Doppler imaging (TDI), which is a new technique, and to compare it with conventional Doppler echocardiography techniques in patients with active rheumatoid arthritis (RA). METHODS: Fifty-two patients with active RA and 47 healthy persons were included in this study. All patients and the control group were evaluated by M-mod, two-dimensional, conventional Doppler echocardiography and TDI. RESULTS: Left ventricular early diastolic (E)/late diastolic (A) flow velocity (E/A ratio) was found to be lower in patients with RA than in the control group (p<0.001). Mitral annular early diastolic (E(m))/late diastolic (A(m)) velocity(E(m)/A(m) ratio) was found to decrease in RA patients compared with the control group (p<0.001). E/E(m) ratio was higher in patients with RA than in the control group (p<0.001). CONCLUSION: Left ventricular diastolic functions were impaired in patients with RA. We have concluded that TDI alone, or together with conventional Doppler echocardiography, is useful for the evaluation of diastolic functions in RA patients.

Adult↗

PubMed1998

Power Doppler imaging and color Doppler flow imaging for the evaluation of normal and pathological vertebral arteries.

Recently, an ultrasound method for vascular applications using the amplitude of the reflected echosignal for the generation of intravascular color signals has been introduced. We compared the utility of this power Doppler imaging (PDI) with conventional color Doppler flow imaging (CDFI) for examination of vertebral arteries (VA). Forty-nine patients with signs and symptoms suggesting ischemia within the posterior circulation were evaluated. Quality of blood flow visualization by PDI and CDFI at the different VA segments was classified according to a four point scale. Furthermore, combined sonographic findings were correlated with the results of digital substraction and/or magnetic resonance angiography (DSA, MRA). Power Doppler imaging provided a significantly superior visualization of the intertransversal VA, whereas display of the intracranial V4 segment was superior significantly on CDFI. Both methods were complementary for the evaluation of the VA at the origin. With respect to the angiographic findings, combined CDFI and PDI achieved a sensitivity of 90.63% and a specificity of 97.22% for the differentiation of healthy and pathologic VAs. Power Doppler imaging is complementary to CDFI for the sonographic assessment of VA disease. Combined use of PDI and CDFI achieves a high sensitivity and specificity, thus increasing diagnostic confidence.

Adolescent↗

PubMed1995

Differentiation of benign and malignant adnexal masses: relative value of gray-scale, color Doppler, and spectral Doppler sonography.

OBJECTIVE: The purpose of this study was to evaluate prospectively the relative usefulness of color Doppler, spectral Doppler, and gray-scale sonography in differentiating benign from malignant adnexal masses. SUBJECTS AND METHODS: A total of 170 adnexal masses in 161 patients were classified prospectively as suggestive of or not suggestive of malignant tumor on the basis of gray-scale morphology, internal flow versus peripheral or no flow, and spectral Doppler pulsatility, as measured by a pulsatility index (PI) threshold of 1.0 and a resistive index (RI) threshold of 0.4. RESULTS: Surgical pathology revealed 123 benign masses and 46 malignant masses. One malignant mass was confirmed by cytologic evaluation of ascitic fluid. On gray-scale analysis, 46 of the 47 malignant masses were classified as suggestive of tumor, and 76 of the 123 benign masses were classified as not suggestive of tumor (sensitivity, 98%; specificity, 62%; negative predictive value [NPV], 99%; and positive predictive value [PPV], 50%). The use of internal color flow as a predictor of malignant tumor yielded a sensitivity of 77%, a specificity of 69%, an NPV of 89%, and a PPV of 49%. The PI and RI values were significantly lower (p < .0001) in malignant masses than in benign masses, although the values overlapped considerably. For a PI of less than 1.0, sensitivity was 67%, specificity was 66%, NPV was 83%, and PPV was 46%. For an RI of less than 0.4, sensitivity was 24%, specificity was 90%, NPV was 73%, and PPV was 50%. CONCLUSION: In our series, a gray-scale prediction of benignity was reliable (NPV = 99%), and a prediction of malignancy was unreliable (PPV = 50%). Internal color flow was not useful as a predictor of malignancy (PPV = 49%). Although the absence of internal or peripheral color flow suggested benignity (NPV = 94%), only 17 (16 benign) of the masses (about 10%) had no flow. Spectral Doppler analysis with RI and PI was not useful, as no reliable discriminatory value with both high sensitivity and high specificity could be found for either parameter because of the overlap in values obtained for benign and malignant masses.

Adnexal Diseases↗

PubMed2000

Doppler ultrasonography and single-fiber laser Doppler flowmetry for measurement of hind limb blood flow in anesthetized horses.

OBJECTIVE: To use Doppler ultrasonography and single-fiber laser Doppler flowmetry (LDF) to evaluate blood flow in the dependent and nondependent hind limbs of anesthetized horses and to evaluate changes in femoral arterial blood flow and microvascular skeletal muscle perfusion in response to administration of phenylephrine hydrochloride or dobutamine hydrochloride. ANIMALS: 6 healthy adult horses. PROCEDURE: Horses were anesthetized and positioned in left lateral recumbency. Doppler ultrasonography was used to measure velocity and volumetric flow in the femoral vessels. Single-fiber LDF was used to measure relative microvascular perfusion at a single site in the semimembranosus muscles. Phenylephrine or dobutamine was then administered to decrease or increase femoral arterial blood flow, and changes in blood flow and microvascular perfusion were recorded. RESULTS: Administration of phenylephrine resulted in significant decreases in femoral arterial and venous blood flows and cardiac output and significant increases in mean aortic blood pressure, systemic vascular resistance, and PCV. Administration of dobutamine resulted in significant increases in femoral arterial blood flow, mean aortic blood pressure, and PCV. Significant changes in microvascular perfusion were not detected. CONCLUSION AND CLINICAL RELEVANCE: Results suggest that Doppler ultrasonography and single-fiber LDF can be used to study blood flows in the hind limbs of anesthetized horses. However, further studies are required to determine why changes in femoral arterial blood flows were not associated with changes in microvascular perfusion.

Anesthetics, Dissociative↗

PubMed1999

[Evaluation of coronary flow velocity and coronary flow reserve before and after coronary angioplasty using transthoracic Doppler echocardiography and Doppler guide wire].

Evaluation of left anterior descending coronary (LAD) blood flow before and after coronary angioplasty was carried out non-invasively by ultrasonic Doppler echocardiography with a newly developed digital, high-frequency, high-resolution transthoracic ultrasonic Doppler flowmeter and a 7.5 MHz probe. The results were compared with those obtained using an intracoronary Doppler guide wire. Sixteen patients, 12 males and 4 females (mean age 57 +/- 14 years) with old myocardial infarction (8 patients) and angina pectoris (8 patients) were studied. Coronary flow reserve was compared following intravenous administration of adenosine triphosphate in 12 patients. The LAD blood flow was detected in 15 of 16 patients. There was a significant increase in the diastolic peak velocity from 22.2 +/- 10.6 to 29.4 +/- 14.6 cm/sec (mean +/- SD) and the coronary flow reserve from 1.8 +/- 0.3 to 2.8 +/- 0.6 (mean +/- SD). There was a good correlation between the data obtained using transthoracic flow measurement and intracoronary flow measurement (r = 0.61, p < 0.05). LAD blood flow can be easily detected parasternally using a digital, high frequency, high-resolution ultrasonic Doppler flowmeter. This method may be applicable for judging the efficacy of coronary angioplasty by measuring coronary flow reserve and for observing the clinical course of the patient non-invasively.

Adenosine Triphosphate↗

PubMed1995

[Echo-color Doppler and echo-Doppler in the diagnosis of carotid body tumors].

Echo-Doppler and Color Flow Doppler examinations, are able to combine the advantages offered by echography with those had with the Doppler exam. In the presence of tumours of the carotid body, these exams can furnish morphological data with regard to tumor size, its precise location and its rapport with contiguous organ as well as data regarding blood flow in the mass itself. The color Flow Doppler exam, in particular, can reveal the echographic aspect and the flow toward and away from the sonde all on the same image. This enables a precise diagnosis of a tumor of the carotid body to be reached even without angiography. The personal experience here reported involves ten cases observed during the last seven years.

Carotid Body Tumor↗

PubMed1991

Evaluation of a theoretical Doppler index to noninvasively estimate peak dP/dt using continuous wave Doppler ultrasound of ascending aortic flow in man.

A theoretical formula for calculation of peak dP/dt was derived using parameters obtained from continuous wave Doppler echocardiography signals of aortic blood flow. The direct proportional relationship between the main variables of this formula and invasively measured peak dP/dt was validated in 20 patients undergoing routine diagnostic cardiac catheterization. Doppler signals of aortic flow were obtained simultaneously to invasive pressure recordings with a 2 MHz continuous wave transducer via the suprasternal echocardiographic window. The Doppler signals were recorded on magnetic tape and measurements were made with digital calipers by two independent, blinded observers. The following parameters were measured: peak velocity (V) and time from onset of ejection to peak velocity (T). V2/T, the variable of the derived formula, was calculated for each of the observer's measured parameters and showed a very high interobserver correlation. The two observers' measurements of each parameter were averaged for each patient and the resulting mean was used in calculating the V2/T and mean acceleration. 4. A good correlation of V2/T with invasively measured peak dP/dt was obtained. Our derived index of left ventricular function showed a higher correlation with peak dP/dt compared to other Doppler indices of ventricular function. V2/T may provide a noninvasive method for estimating peak dP/dt.

Aorta↗

PubMed1998

Doppler study of mesenteric, hepatic, and portal circulation in alcoholic cirrhosis: relationship between quantitative Doppler measurements and the severity of portal hypertension and hepatic failure.

To determine the relationship between quantitative Doppler parameters of portal, hepatic, and splanchnic circulation and hepatic venous pressure gradient (HVPG), variceal size, and Child-Pugh class in patients with alcoholic cirrhosis, we studied forty patients with proved alcoholic cirrhosis who underwent Doppler ultrasonography, hepatic vein catheterization, and esophagoscopy. The following Doppler parameters were recorded: time-averaged mean blood velocity, volume flow of the main portal vein flow, and resistance index (RI) of the hepatic and of the superior mesenteric artery. Doppler findings were compared with HVPG, presence and size of esophageal varices, and Child-Pugh class. There was a significant inverse correlation between portal velocity and HVPG (r = -.69), as well as between portal vein flow and HVPG (r = -.58). No correlation was found between RI in the hepatic artery or superior mesenteric artery and HVPG. No correlation was found between portal vein measurements and presence and size of varices. Severe liver failure was associated with lower portal velocity and flow. In patients with alcoholic cirrhosis, only portal vein blood velocity and flow, but neither hepatic nor mesenteric artery RI, are correlated to the severity of portal hypertension and to the severity of liver failure.

Adult↗

PubMed1994

Doppler echocardiography during transesophageal atrial pacing in the detection of coronary artery disease. Stress Doppler echocardiography in the detection of coronary artery disease.

The aim of this study was to assess the applicability of the Doppler echocardiogram (EchoKG) during transesophageal atrial pacing (TAP) with respect to the detection of coronary artery disease (CAD). Aortic flow peak velocity (PV), mean acceleration (MA), stroke distance (SD), minute distance (MD) and time to PV were measured using pulsed Doppler EchoKG during sinus rhythm and at pacing rates of 120 and 140 bpm in 11 patients, taken as subjects, with CAD defined by coronary arteriography and 15 patients without CAD (the control group). Similar changes of PV, SD, MD and time to PV during TAP were observed in subjects with and without CAD. Only changes of MA were different between subjects with and without CAD:MA during TAP remained unchanged in the control group and decreased from 1055.2 +/- 49.7 cm/s2 (baseline) to 829.0 +/- 55.9 cm/s2 at pacing rate 140 bpm (p < 0.05) in subjects with CAD. On the basis of these data we suggest a new criterion for the detection of hemodynamically significant CAD: decrease of MA at a pacing rate of 140 bpm > 15% of initial value. Its specificity and sensitivity in the detection of CAD were respectively 87% and 82%. We conclude that the Doppler EchoKG during TAP is a relatively simple and reliable method for the diagnosis of CAD, and that the response of the Doppler EchoKG parameter of MA to TAP is a sensitive and specific index, useful for the detection of significant coronary artery stenosis.

Cardiac Pacing, Artificial↗

PubMed2005

Diastolic function abnormalities in active rheumatoid arthritis evaluation by conventional Doppler and tissue Doppler: relation with duration of disease.

OBJECTIVE: The aim of this study was to evaluate left ventricular diastolic function in patients with active rheumatoid arthritis (RA), analyzing conventional Doppler and tissue Doppler echocardiographic imaging (TDI) which is a new echocardiographic application, with special regard to disease duration. METHODS: Fifty-two patients with active RA and 47 healthy persons were included in this study. Duration of disease ranged from 3 to 324 months (mean 76+/-85 months). All patients and the control group were evaluated by M-mod, two-dimensional, conventional Doppler echocardiography and TDI. RESULTS: Among conventional Doppler transvalvular mitral flow parameters, late diastolic flow velocity (A) and deceleration time (DT) values were higher in patients with RA than that in the control group (p<0.001). E (early diastolic flow velocity)/A ratio was found to be lower in patients with RA than that in the control group (p<0.001). Mitral annular early diastolic velocity (E (m)), among TDI parameters, was found to be lower in patients with RA than that in the control group (p<0.001). E (m)/A (m) (mitral annular late diastolic velocity) ratio was found to be lower in RA patients compared with that in the control group (p<0.001). The relation was found between A (r=0.43, p=0.001), DT (r=0.30, p=0.03), E/A ratio (r=0.40, p=0.004), E (m) (r=0.32, p=0.02), E (m)/A (m) ratio (r=0.30, p=0.03), and E/E (m) (r=0.32, p=0.02), with disease duration in patients with RA. CONCLUSION: At present, it is concluded that active RA patients, in the absence of clinical evidence of heart disease, show diastolic dysfunction characterized by impaired E/A ratio, E (m)/A (m) ratio, and DT. The relation between diastolic dysfunction and disease duration suggests a subclinical myocardial involvement.

Arthritis, Rheumatoid↗