Pulsed-wave Doppler Ultrasonography Research Articles

Angle dependence and transit time effect in Doppler flow measurement

Objective: In clinical practice, obvious differences exist between the Doppler theory which does not allow a frequency shift at right angles of insonation, and the fact that a frequency is generated. Possible technical and physical causes were evaluated in our study. Methods: A laminar, non-pulsatile flow model was insonated between 35° and 155° with pulsed wave (pw) Doppler sonography incorporated in a duplex scanner. Results: For all angles tested the maximum frequencies were higher than predicted by the Doppler formula. The frequency shift observed at perpendicular insonation cannot be explained by the Doppler theory. Conclusions: The results obtained can be explained by intrinsic spectral broadening (ISB) caused by the transit time effect or equivalently by the geometry of the ultrasonic beam. These effects have to be considered when the maximum frequency is employed to quantify flow volume or when spectral broadening is used as an indicator of disturbed flow.

Angle dependence and transit time effect in Doppler flow measurement

Objective: In clinical practice, obvious differences exist between the Doppler theory which does not allow a frequency shift at right angles of insonation, and the fact that a frequency is generated. Possible technical and physical causes were evaluated in our study. Methods: A laminar, non-pulsatile flow model was insonated between 35° and 155° with pulsed wave (pw) Doppler sonography incorporated in a duplex scanner. Results: For all angles tested the maximum frequencies were higher than predicted by the Doppler formula. The frequency shift observed at perpendicular insonation cannot be explained by the Doppler theory. Conclusions: The results obtained can be explained by intrinsic spectral broadening (ISB) caused by the transit time effect or equivalently by the geometry of the ultrasonic beam. These effects have to be considered when the maximum frequency is employed to quantify flow volume or when spectral broadening is used as an indicator of disturbed flow.

Assessment of early placental development in the cynomolgus monkey (Macaca fascicularis) using colour and pulsed wave Doppler sonography

Colour flow mapping and pulsed wave Doppler were used to assess the process of placental growth and development in the cynomolgus monkey from 32 to 71 days gestational age. Fetal and maternal vessels were reliably visualised and insonated. Accurate longitudinal non-invasive assessment of placentation is possible using this technique.

Hypoplasie de l'aorte abdominale, cause rare d'hypertension artérielle du grand enfant

The majority of children with secondary hypertension have a renal abnormality or renovascular lesions. Coarctation of the aorta is also a classical cause, rarely located to the abdominal aorta. Case reports. - Two girls, 11 and 12 years-old, were suspected of having recent sustained hypertension. Pulsed-wave doppler ultrasonography and angiography showed abdominal aortic hypoplasia associated with renal artery stenosis, unilateral in one patient and bilateral in the other. Both patients became normotensive 10 and 18 months, respectively, after corrective vascular surgery. Conclusion. - Examination of the abdominal part of the aorta is mandatory in all patients with hypertension.

Influence of Jet Direction on Pulmonary Vein Flow Patterns in Severe Mitral Regurgitation

Pulmonary vein flow patterns measured with transesophageal echocardiography have been used recently to assess the severity of mitral valve regurgitation.This study was designed to determine whether regurgitant jet direction selectively influences the pattern of flow in right and left pulmonary veins. Thirty-seven patients undergoing mitral valve repair or replacement for severe valvular regurgitation were studied intraoperatively with biplane transesophageal echocardiography. Regurgitant jets were classified by color flow mapping as central or wall, with the latter further classified as septal, lateral, anterior, or posterior in the two orthogonal scan planes. Pulmonary vein flow patterns were measured with pulsed wave Doppler ultrasonography and categorized as showing normal, blunted, or reversed systolic flow. Right and left pulmonary vein flow patterns were identical in the majority of patients studied (78%). Eight patients had discordant flow patterns. In seven of eight patients, the more abnormal pattern was seen in the right pulmonary vein, despite the fact that the regurgitant jets were directed centrally in four of these seven patients. Since discordant pulmonary vein flow patterns occurred in 5 of 15 patients (33%) with central jets, but in only 3 of 22 patients (14%) with eccentric wall jets, it is unlikely that mitral regurgitation jet direction per se causes predictable and selective unilateral alteration in pulmonary vein flow patterns. (Anesth Analg 1995;80:486-91)

Influence of Jet Direction on Pulmonary Vein Flow Patterns in Severe Mitral Regurgitation

Pulmonary vein flow patterns measured with transesophageal echocardiography have been used recently to assess the severity of mitral valve regurgitation. This study was designed to determine whether regurgitant jet direction selectively influences the pattern of flow in right and left pulmonary veins. Thirty-seven patients undergoing mitral valve repair or replacement for severe valvular regurgitation were studied intraoperatively with biplane transesophageal echocardiography. Regurgitant jets were classified by color flow mapping as central or wall, with the latter further classified as septal, lateral, anterior, or posterior in the two orthogonal scan planes. Pulmonary vein flow patterns were measured with pulsed wave Doppler ultrasonography and categorized as showing normal, blunted, or reversed systolic flow. Right and left pulmonary vein flow patterns were identical in the majority of patients studied (78%). Eight patients had discordant flow patterns. In seven of eight patients, the more abnormal pattern was seen in the right pulmonary vein, despite the fact that the regurgitant jets were directed centrally in four of these seven patients. Since discordant pulmonary vein flow patterns occurred in 5 of 15 patients (33%) with central jets, but in only 3 of 22 patients (14%) with eccentric wall jets, it is unlikely that mitral regurgitation jet direction per se causes predictable and selective unilateral alteration in pulmonary vein flow patterns.

Differential breast tumor diagnosis by comparing blood circulation of the tumor with the contralateral breast using color coded, pulsed Doppler ultrasound

74 breast tumor patients were preoperatively examined by means of colour and pulsed-wave Doppler sonography using the ultrasonic instrument ALT Ultramark 9 HDI with a broad-band linear scanner, 5-10 MHz. The Doppler flow velocity waveforms, from the vessels of the mammary lesion (affected breast) and the corresponding quadrant of the contralateral breast (non-affected breast), respectively, were compared in respect of the four parameters maximal systolic velocity, minimal diastolic velocity, pulsatility index (PI) and resistance index (RI). In 48 cases we succeeded in representing arterial vessels both inside the affected and the contralateral breast. The aim of the study was to examine whether these parameters show a significantly different degree of deviation in correlation with the tumours being either benign or malign. In cases with benign lesions (n = 24) we did not find any significant differences in all the parameters that we examined. In cases with cancer, however (n = 18), a significantly higher systolic velocity was found in the affected breast compared to the contralateral breast, but there were no differences in the other parameters. Although the quantitative Doppler measurements are angle-dependent parameters, the study showed that the maximal velocity in the affected breast compared to the contralateral breast is the most useful parameter in differential diagnosis of breast tumours.

Non-puerperal mastitis in real time and color Doppler ultrasound

Differential diagnosis distinguishing between nonpuerperal mastitis and inflammatory cancer of the breast is difficult, the conventional method being mammography. In our study, we present the typical findings gained by sonography of 16 patients with nonpuerperal mastitis. They do not differ significantly from those cases with breast cancer. From these 16 patients, 7 were additionally examined using Colour and Pulsed Wave Doppler Sonography. International literature offers little practical knowledge in this field. In the immediate surroundings of the inflammation, we were able to represent up to four arterial vessels per patient. The parameters of the flow velocity wave form of these vessels were compared to those of the vessels in the correspondent quadrant of the contralateral breast. In all cases, the maximum systolic and the minimum end diastolic velocities were higher than in the contralateral breast, giving evidence of an increased vascularity. In 6 cases, the pulsatility and resistance indices in the inflammatory vessels were lower because of a decreased peripheral resistance of the vessel. Under therapy with antibiotics or Bromocriptine, these parameters were equalized in both breasts. The model of nonpuerperal mastitis shows, that Colour and Pulsed Wave Doppler Sonography makes it possible to differentiate tumours of the breast on the basis of an analysis of their vascularity and the comparison with the parameters of the vessels in the contralateral breast. The effects of a pharmacological therapy on the vascularity of breast tumours can also be measured with this method.

139 PORTOSYSTEMIC ENCEPHALOPATHY DUE TO PERSISTENCE OF AN OPEN DUCTUS VENOSUS ARANTII

A girl was followed from birth to age 6 y because of congenital heart defect and persisting hypergalactosemia without enzyme defect. An open ductus venosus was suspected, remained undetected by conventional 2-dimensional ultrasonography but was demonstrated by combined color and pulsed wave Doppler sonography at age 4 y. Average forward flow in the portocaval shunt was 240 ml/min; intrahepatic venous flow or other intra- or retroperitoneal venous collaterals were not seen. Episodes of sleepiness, withdrawal, apathy, occasional vomiting, complaints of headache inbetween, starting at age 3.5 y, were first misinterpreted as migraine. After age 4, she occasionally smelled of ammonia, had mild intention and head tremor, dysmetria, rubeosis of face, hands and feet, insecurity of gait, moderate hyperammonemia, elevated liver enzymes in serum. Her liver remained small, by ultrasound. She was treated with low-protein diet, lactulose, sodium benzoate, with limited success. Tentative treatment with flumazenil is in progress. Hypergalactosemia without enzyme defect is an early sign of duct persistence. The early onset of portosystemic encephalopathy correlates with the large volume of shunted splanchnic blood.

A comparative study of continuous- and pulsed-wave Doppler velocimetry in fetal and uteroplacental circulation.

Continuous-wave and pulsed-wave Doppler ultrasonography are the two common methods used to study the fetal and uteroplacental circulation. We used both methods in the same patient population in three different gestations and in various fetal and uteroplacental vessels to compare the results from both machines. Thirty-one normal patients were studied at 20, 28, and 36 weeks gestation. The results showed significant correlation with no statistically significant differences between the two types of machines for the peak systolic/end-diastolic ratios and resistance index for the umbilical artery and uterine arteries. Significant differences, however, were demonstrated when the arcuate artery was studied, or when the pulsatility index was used for comparison. We therefore conclude that when different machines are used for study, comparison of the results is only valid for selected vessels and indices. Results for arcuate arteries and pulsatility index should be compared with caution.

Measurement of Systolic-Diastolic Ratio in the Umbilical Artery by Continuous-Wave and Pulsed-Wave Doppler Ultrasound: Comparison at Different Sites

Measurement of Systolic-Diastolic Ratio in the Umbilical Artery by Continuous-Wave and Pulsed-Wave Doppler Ultrasound: Comparison at Different Sites

Measurement of Systolic-Diastolic Ratio in the Umbilical Artery by Continuous-Wave and Pulsed-Wave Doppler Ultrasound: Comparison at Different Sites

Analysis of umbilical artery flow velocity waveforms, especially systolic-diastolic (S-D) ratio, can predict some pregnancy abnormalities. Most of the earlier studies did not specify the exact segment of umbilical artery sampled. We studied 53 normal singleton pregnancies between 18-41 weeks' gestation to compare S-D ratio measurements of the umbilical artery at different sites: 1) abdominal insertion site, 2) placental insertion site, 3) mid-cord, and 4) an undetermined site. The mean S-D ratio was significantly different (P less than .01) at various segments of the umbilical artery--higher near the abdominal insertion site when compared with the mid-cord, near-placental, and undetermined sites. The S-D ratio at mid-cord was higher than at the undetermined site and the placental insertion site. The near-placental-site S-D ratio was not different from the undetermined site. A lower S-D ratio at the undetermined site may not adequately reflect the true physiologic status of the fetus. Specifying the site of measurement should be an integral part of any report, in order to describe accurately the pathophysiology of fetoplacental circulatory diseases.

Noninvasive assessment of cerebral collateral blood supply through the ophthalmic artery.

We assessed the potential of 2-MHz pulsed-wave transorbital Doppler ultrasonography to delineate the role of the ophthalmic artery as a source of collateral cerebral blood supply by comparing oculopneumoplethysmography, transorbital Doppler ultrasonography, periorbital continuous-wave Doppler ultrasonography, and transcranial Doppler ultrasonography in 25 patients with unilateral internal carotid artery occlusion and five controls with 10 normal internal carotid arteries. Systolic ophthalmic artery blood velocity was reduced ipsilateral to an internal carotid artery occlusion (38.2 +/- 10.2 cm/sec) compared with the contralateral and control velocities (46.0 +/- 10.3 and 47.5 +/- 6.8 cm/sec, respectively; p less than 0.05). Ophthalmic systolic pressure measured by oculopneumoplethysmography was 94.7 +/- 13.2 mm Hg ipsilateral to an internal carotid artery occlusion compared with 108.4 +/- 15.3 mm Hg on the contralateral side (p less than 0.01). Transorbital and periorbital Doppler ultrasonography detected reversed ophthalmic artery blood flow ipsilateral to an internal carotid artery occlusion in 44.0% and 40.0% of the patients, respectively. Systolic middle cerebral artery blood velocity was 55.2 +/- 22.3 cm/sec ipsilateral to an internal carotid artery occlusion compared with 79.4 +/- 23.5 cm/sec on the contralateral side (p less than 0.05) and 101.2 +/- 18.9 cm/sec in the controls (p less than 0.05). Reversed ophthalmic artery blood flow was associated with a low middle cerebral artery blood velocity and lack of major intracerebral collaterals. Transorbital Doppler ultrasonography permits noninvasive evaluation of the ophthalmic artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Recording of blood flow velocity waveforms in the uteroplacental and umbilical circulation: Reproducibility study and comparison of pulsed and continuous wave Doppler ultrasonography

Reproducibility of the blood flow velocity waveforms (FVW) recorded from the umbilical artery and the arcuate arteries on the right and left side of the placenta was examined in 8 women with normal pregnancies and anterior placentas. The FVW were recorded using a 2-MHz pulsed Doppler ultrasound system in combination with a real-time linear-array scanner. The FVW were characterized by the pulsatility index (PI) and systolic/diastolic (S/D) ratio. For the PI, the mean coefficients of variation between six operator pairs in the umbilical artery and the left and right arcuate arteries were 8.4%, 26%, and 21.5%, respectively. These findings suggest that, in clinical practice, the umbilical artery FVW is reproducible, but the usefulness of arcuate artery FVW is limited by the wide variation of Doppler signals. Paired recordings of FVW were obtained from the umbilical, arcuate, and uterine arteries using pulsed wave and continuous wave Doppler ultrasonography in a randomized order in another 21 pregnant women with anterior placentas. There was no difference between the two Doppler modes for any of the measured waveform indices.

Pulsed wave Doppler velocimetry in the descending aorta of chronically instrumented fetal sheep

Pulsed wave Doppler sonography was used to determine peak systolic velocity (Vpeak), mean maximum velocity (Vmean) and Pulsatility Index (PI) in the descending aorta of chronically instrumented, unanesthetized fetal sheep (days 120-130 of pregnancy). Measurements were done 1-4 days after surgery using a duplex mechanical sector scanner (4.5 MHz) and offset attached pulsed wave Doppler probe (2.25 MHz) during periods of control, intrauterine cooling and rewarming. Mean values derived from the envelope curve of maximum shift frequencies were (controls): thoracic: Vmean 60.9 +/- 9.1 cm/sec, Vpeak 118.9 +/- 17.8 cm/sec, PI 1.57 +/- 0.24; abdominal: Vmean 49.6 +/- 10.9 cm/sec, Vpeak 98.9 +/- 20.4 cm/sec, PI 1.59 +/- 0.41. Vpeak was positively correlated to arterial pressure (r = 0.23) and PI showed an inverse correlation to heart rate (r = -0.22). During cold stress (reduction of fetal core temperature by 2.7 degrees C) and consecutive rewarming Vpeak and Vmean were positively correlated to fetal core temperature and arterial pressure (r = 0.2-0.26). PI revealed a weak negative dependency from core temperature and heart rate (r = -0.19 and -0.18 respectively).

A Comparative Study of Fetal Umbilical Velocimetry with Continuous and Pulsed-wave Doppler Ultrasonography in High-risk Pregnancies: Relationship to Outcome

A Comparative Study of Fetal Umbilical Velocimetry with Continuous and Pulsed-wave Doppler Ultrasonography in High-risk Pregnancies: Relationship to Outcome

A comparative study of fetal umbilical velocimetry with continuous- and pulsed-wave Doppler ultrasonography in high-risk pregnancies: Relationship to outcome

Systolic/diastolic ratios of umbilical velocimetry obtained with either continuous-wave or pulsed-wave Doppler ultrasonography have been used to assess downstream placental vascular resistance and fetal well-being. The purpose of this study is to compare the efficacy of systolic/diastolic ratios obtained by continuous-wave and pulsed-wave Doppler ultrasonography in the prediction of poor pregnancy outcome. Continuous-wave and pulsed-wave umbilical velocimetry was performed and systolic/diastolic ratios were measured in 200 high-risk pregnancies in the third trimester by use of Angioscan III and a General Electric RT 3600 scanner, respectively. A total of 165 study participants had normal systolic/diastolic ratios and 35 participants had elevated ratios (greater than 3.0) with both continuous-wave and pulsed-wave Doppler ultrasonography. Both methods identified 35 participants with abnormal ratios, and none of the women was misclassified by either method. The pulsed-wave and continuous-wave values for 35 participants with elevated ratios were 6.35 +/- 1.52 and 6.23 +/- 1.58, respectively; values for 165 participants with normal ratios were 1.95 +/- 0.40 and 1.96 +/- 0.41, respectively (not significantly different). Participants with elevated systolic/diastolic ratios within 7 days of delivery had significantly higher incidence of adverse pregnancy outcome as judged by small-for-gestational-age fetuses, presence of meconium at delivery, fetal distress in labor, cesarean sections and 5-minute Apgar scores less than 7. Fetuses with elevated ratios were delivered at an earlier gestational age (34 +/- 1.2 weeks), had lower birth weights (1422 +/- 151 gm), and spent more time in the neonatal intensive care unit (17.1 +/- 5.2 days), compared with fetuses with normal ratios (delivered at 38.5 weeks +/- 0.9 weeks, 3100 +/- 210 gm birth weights, and 2 +/- 0.2 days spent in neonatal intensive care units, respectively, p less than 0.05). We therefore conclude that continuous-wave and pulsed-wave Doppler ultrasonography produce similar results with regard to systolic/diastolic ratios in high-risk pregnancies, and either method appears to be a valuable adjunct in the surveillance of high-risk pregnancies.

Fetal Umbilical Velocimetry Using Continuous-Wave and Pulsed-Wave Doppler Ultrasound in High-Risk Pregnancies: A Comparison of Systolic to Diastolic Ratios

Systolic to diastolic (S/D) ratios of umbilical velocimetry using either continuous-wave or pulsed-wave Doppler ultrasound have been used to assess downstream placental resistance. The purpose of this study was to compare the S/D ratios obtained by both types of instrumentation to determine whether there are significant differences between measurement values. Umbilical velocimetry was performed on 200 high-risk pregnancies in the third trimester using the Angioscan III to obtain continuous-wave velocimetry and the General Electric RT3600 to obtain pulsed-wave velocimetry. Systolic to diastolic ratios were considered abnormally high if they were greater than 3. One hundred sixty-five patients had normal S/D ratios and 35 patients had elevated ratios on both continuous-wave and pulsed-wave ultrasound. There was no significant difference in the mean S/D ratios obtained by either method for the entire population (continuous-wave S/D 2.81 +/- 1.79, pulsed-wave S/D 2.71 +/- 1.83, R = 0.98), the normal group (continuous-wave S/D 1.96 +/- 0.41, pulsed-wave S/D 1.95 +/- 0.40, R = 0.91), and the abnormal group (continuous-wave S/D 6.23 +/- 1.58, pulsed-wave S/D 6.35 +/- 1.52, R = 0.94). Least-square regression was performed to model the relationships between pulsed wave and continuous wave, with both used as dependent variables. The slopes and intercept for the normal and abnormal groups were evaluated and were significantly different (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of systolic murmurs by Doppler ultrasonography.

Non-invasive continuous and pulsed wave Doppler ultrasonography was performed in 102 consecutive patients with clinically ill defined systolic murmurs to differentiate between flow murmurs, mitral regurgitation, aortic stenosis, and ventricular septal defect, as well as to assess the severity of aortic stenosis. Diagnoses with the Doppler method were based on velocity, direction, and duration of flow signals and were subsequently verified by cardiac catheterisation in all patients. Multiple evaluations were made in 31 patients. Sensitivity and specificity were 0.87 and 0.77 in mitral regurgitation, 0.9 and 1.0 in aortic stenosis, and 1.0 and 1.0 in ventricular septal defect. In 67 patients the estimation of severity of aortic stenosis using the Doppler technique to calculate aortic pressure gradients from maximum flow velocity was significantly correlated with that determined at catheterisation. It is concluded that Doppler ultrasonography is a highly useful technique for the non-invasive evaluation of clinically ill defined systolic murmurs.