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At least 19 recordsLinked to original sources
PubMed1999

[Ultrasonography of placenta previa at the third trimester of pregnancy: research for signs of placenta accreta/percreta and vasa previa. Prospective color and pulsed Doppler ultrasonography study of 45 cases].

OBJECTIVES: In a population of 45 placenta previa observed at third trimester of gestation we have tried to make the prenatal diagnosis of placenta percreta and vasa previa with color and pulsed Doppler ultrasonography. MATERIALS AND METHODS: We used a transabdominal sonography with full bladder and a transvaginal sonography with empty bladder. The first images obtained showed 20 placenta previa over the internal cervical os, 3 marginal and 22 low-lying placenta previa. We tried to find evidence of placenta percreta with gray-scale ultrasonography (loss of normal hypoechoic retroplacental myometrial zone, focal disruption of the uterine serosa and surrounding tissues, presence of intra placental lacunae) and with color and pulsed Doppler (arterial vessels with a diastolic flow value less than the flow value of a spiral artery behind the placenta, arterial vessels crossing from the placenta to surrounding tissues, intraplacental lacunae with arterial flow). We tried to find evidence of vasa previa in color and pulsed Doppler (a fetal vessel in seen above the lower segment of the uterus and below the fetal head. There is no change in the location of the vessel despite positional changes in both mother and fetus). The positivity of one sign in gray-scale ultrasonography or in color and pulsed Doppler led us to believe that the patient was affected by the anomaly. The final diagnosis of abnormal adherence of the placenta and of vasa previa was made on histological examination. RESULTS: Among the 20 placenta previa over the internal cervical os, we found 1 placenta percreta, 1 placenta accreta and 3 cases of vasa previa. In spite of our limited sample of cases of abnormal adherences, our results showed that gray-scale ultrasonography was sufficient to make a prenatal diagnosis of placenta accreta/percreta. Negative predictive value is 100% on a sample of 43 patients with no abnormal placental adherence. Color and pulsed Doppler brought no further evidence. In our population, color and pulsed Doppler had 100% positive predictive value for diagnosis of vasa previa. CONCLUSION: We found the only 2 cases of abnormal adherent placental fragments and the 3 cases of vasa previa present in our population. The study of the lower segment of the uterus should be thorough as abnormal zones may be small-sized. Color Doppler is the reference technique for sighting vasa previa and gray-scale ultrasonography for abnormal adherences of the placenta.

Female↗
PubMed1995

Prenatal diagnosis of gastroesophageal reflux by color and pulsed Doppler ultrasonography in a case of congenital pyloric atresia.

A case of pyloric atresia diagnosed in the third trimester is described. Real-time ultrasonographic examination revealed polyhydramnios, enlarged stomach, evident gastric peristalsis and esophageal dilatation. Color and pulsed Doppler studies of the gastroesophageal junction revealed the presence of a biphasic flow pattern that was consistent with gastroesophageal reflux.

Adult↗
PubMed1994

Diabetes mellitus in pregnancy and the assessment of umbilical artery waveforms using pulsed Doppler ultrasonography.

The utility of Doppler ultrasonography as a means of assessing potential alterations of vascular resistance prior to fetal or maternal compromise is very attractive. We investigated this relationship by prospectively performing Doppler studies of the fetal umbilical artery in 56 diabetic patients, 14 of whom had varying degrees of vascular complications. When regression curves were established for the S/D ratio, the Pourcelot index, and the resistance index of the fetal umbilical artery, the mean Doppler values were higher in diabetic patients with vasculopathy than in nondiabetic control patients or in diabetic patients without vasculopathy. The third trimester S/D ratio was greater than 3.0 in almost 50% of patients with vasculopathy. A tendency toward adverse outcomes was observed at S/D ratios approaching 4.0. Statistically significant correlations were found between elevated Doppler indices and maternal vasculopathy associated with hypertension and worsening renal insufficiency. Intrauterine growth retardation and neonatal metabolic complications were also significantly correlated with elevated Doppler indices. There was, however, no correlation between Doppler indices and glucose values, although most were within a euglycemic range. The aforementioned data indicate an increased resistance circuit among diabetics with vasculopathy, which may reflect a relative reduction in basal uteroplacental blood flow and the need for cautious interpretation of Doppler indices in these patients.

Adult↗
PubMed1999

Assessment of Doppler velocimetry of the fetal umbilical artery by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography plus color flow mapping.

The Doppler signal of blood flow originates from the sonographic scattering from the circulating red blood cells. However, the physics of blood flow is complex as expressed by the Bernoulli equation, and the flow velocity at different positions in the laminar flow of the same vessel is variable. Using multigate spectral Doppler scanning, we recorded multiple Doppler flow signals over a segment of the umbilical artery and compared the results with traditional pulsed Doppler ultrasonography. The intraobserver variations of the pulsatility index, the resistive index, and the systolic-to-diastolic ratio were evaluated in 30 human fetuses between 29 and 42 weeks of gestation. The correlation coefficient was calculated to establish the relationship between the results of multigate spectral Doppler scanning and the traditional pulsed Doppler ultrasonographic method. The Doppler indices of these two measurements are all significantly correlated. However, since a significant difference exists between the Doppler flow measurements of multigate spectral Doppler scanning and the traditional pulsed Doppler ultrasonographic method, the range of measurement agreement for these two methods suggests that this difference should be taken into account in the interpretation of Doppler flow velocity measurements.

Female↗
PubMed1998

Pulsed Doppler ultrasonography guidance for catheterization of the subclavian vein: a randomized study.

BACKGROUND: Catheterization of the subclavian vein may lead to severe complications. The current randomized study compared a technique of pulsed Doppler ultrasonography guidance and the standard method for subclavian vein catheterization. METHODS: Standard and Doppler ultrasonography guidance methods were performed by the same physician in 286 patients, 143 in each group. Primary end points were immediate complications (arterial puncture, pneumothorax, wrong position of catheter tip), failures, the number of subclavian vein catheterizations with immediate complication or failure, the number of skin punctures per catheterization, and the time to placement of the guide wire. The secondary end points were the determination of predicting factors of successful cannulation in each group. RESULTS: Both groups were similar according to morphologic parameters of the patients. A greater number of subclavian vein catheterizations were performed on the right side using Doppler guidance (105 vs. 73, P < 0.01). Doppler guidance decreased complications (5.6% vs. 16.8%, P < 0.01), largely because of a smaller number of catheters for which the tip was defined to be in incorrect position (0.7% vs. 7.7%, P < 0.01). The time to catheterization was longer with Doppler guidance (300 vs. 27 s, P < 0.001). Failures, catheterizations of the subclavian vein with immediate complications or failure, and the total number of skin punctures per catheterization were similar in both groups. Using Doppler guidance, the presence of a good Doppler signal (124 of 143) was predictive of successful catheterization (123 successful cannulations, P < 0.001). CONCLUSIONS: Doppler guidance reduces the incidence of inappropriately positioned subclavian catheters.

Adult↗
PubMed1984

Assessment of tricuspid regurgitation by pulsed Doppler ultrasonography of the hepatic veins.

Pulsed Doppler echocardiography was tested to assess the degree of tricuspid regurgitation (TR), classified by right ventriculography, in 47 patients. Forty-eight subjects without TR served as controls (39 with sinus rhythm and 9 with atrial fibrillation). Two Doppler methods were used: the distance of systolic turbulence within right atrium from the tricuspid plane and the quantitative analysis of the flow-velocity traces from the hepatic veins (HVs). Right atrial systolic turbulence was found in 41 of 47 patients with TR and in none of the control subjects, and moderately correlated with the angiographic grading (r = 0.57). In control subjects, TR flow-velocity traces from the HVs showed 2 anterograde flow waves, systolic and diastolic. The ratio of anterograde systolic/anterograde diastolic velocity was more than 0.6 in 38 subjects with sinus rhythm and in 8 with atrial fibrillation. Twenty-two control subjects had a positive wave (designated as "v") coincident with the end of T wave. In 30 patients with TR, a retrograde holosystolic wave was present. Of the remaining patients, 12 had a ratio of anterograde systolic/anterograde diastolic velocity less than 0.6. Fifteen had an end-systolic "v-like" wave, which occurred earlier than the v wave in control subjects (p less than 0.001). In patients with TR, maximal velocities of the anterograde diastolic and retrograde systolic flow correlated with angiographic grading (r = 0.74 and 0.73, respectively). An anterograde diastolic flow velocity more than 26 cm/s and a retrograde systolic flow velocity more than 16 cm/s excluded mild TR. Analysis of Doppler recordings of the HVs is valuable to semiquantitatively assess TR, complementing the right atrial Doppler findings.

Adolescent↗
PubMedDate not supplied

Vascular signals from pleura-based lung lesions studied with pulsed Doppler ultrasonography.

Vascular signals arising from pleura-based lung lesions were studied in 50 patients using pulsed Doppler ultrasonography. Twenty-seven had malignant lesions and 23 benign lesions. In 24/27 of the malignant masses, we observed no Doppler signals: in 2 cases, a low-velocity, turbulent, pulsatile flow was demonstrated; in 1 case pulsed Doppler ultrasonography showed only a low-velocity, continuous flow. In 20/23 of the benign lesions, we found 2 types of Doppler signal waveforms: an irregularly pulsatile, venous-like signal, and a regularly pulsatile, arterial-like waveform. The last 8 patients of our series underwent color Doppler ultrasound examination, which demonstrated the presence of arterial and venous vessels in 4 benign lesions and the absence of blood flow in 4 malignant masses. To our knowledge, we report for the first time the ability of obtaining Doppler signals from a variety of lung lesions. The actual clinical relevance of this application requires further studies.

Adult↗
PubMed1990

Comparison of dynamic image and pulsed Doppler ultrasonography for the diagnosis of intrauterine growth retardation.

Dynamic image and pulsed Doppler ultrasonography were used to evaluate 104 potentially growth-retarded fetuses. The two techniques were compared, and then used together to predict whether or not the neonate would be growth retarded. Both ultrasonic diagnostic techniques showed good correlation with neonatal outcome, but their combined use improved diagnostic accuracy.

Blood Flow Velocity↗
PubMed1992

Diagnosis of portal vein tumor thrombus by pulsed Doppler ultrasonography.

The blood flow of portal vein thrombus was studied by pulsed Doppler ultrasonography in 21 patients with tumor thrombus and 14 with blood clot thrombus. Pulsatile waves were observed in 19 of the 21 with tumor thrombus, with backward continuous waves in 3, and forward/backward continuous waves in 2. In contrast, forward continuous waves were observed in 2 of the 14 with blood clot thrombus. By color imaging, the blood flow could be observed in 9 of 14 with tumor thrombus, but in 1 of 7 with blood clot thrombus. Pulsatile and backward continuous waves were characteristic of tumor thrombus.

Adult↗
PubMed1995

[Pulsed Doppler ultrasonography to measure the vasoactive effects of hemoglobin-dextran 10-benzene-tetracarboxylate, a potential erythrocyte substitute].

The effects of Dextran-Benzene-Tetracarboxylate-Hemoglobin (Dex-BTC-Hb), a chemically-modified hemoglobin-based oxygen carrier, on the vascular tone were compared to those of standard solutions, i.e. the animal's own blood and a 50 milligrams albumin solution, by measuring the carotid blood flow velocity, the mean arterial pressure, the heart rate and respiratory frequency, in anesthetized Hartley guinea pigs after a hemorragic shock. Stroma-free hemoglobin induced 40% hypertension and a 110% rise in blood flow velocity immediately after injection. The velocity was still increased 38%, 3 hours after injection. The calculations of the vascular resistances showed an increase in carotid vascular tone. Dex-BTC-Hb brought about 35% hypertension for two hours with no significant modifications of the vascular tone. These effects are similar to those of the albumin solution. These results indicate that, unlike stroma-free hemoglobin, Dex-BTC-Hb does not significantly affect the vascular tone, probably because of its slight interaction with the factors that regulate vascular tone.

Animals↗
PubMed1999

New hemodynamic approach to angiogenesis: color and pulsed Doppler ultrasonography.

RATIONALE AND OBJECTIVES: To determine the capacity of color and spectral Doppler ultrasonography (US) to quantify angiogenesis in vivo and to characterize low-resistance intratumor blood flow. METHODS: Thirty-two tumors, xenografted into mice, were studied with Doppler US. The number of intratumor vessels visualized with color Doppler US was compared with the density of microvessels and the number of vessels >100 microm determined by histologic examination. The resistance index and the peak systolic velocities were evaluated. RESULTS: The number of intratumor vessels visualized by color Doppler US was correlated with the number of vessels >100 microm (P<0.001) determined histologically. When vessel density was >30, intratumor vessels were always detected by color Dopper US. The resistance index and peak systolic velocities were significantly lower in intratumor than in peritumor vessels. CONCLUSIONS: Color Doppler US evaluated tumor angiogenesis accurately. Spectral analysis confirmed the low resistance of intratumor blood flow.

Animals↗
PubMed1998

[Exploration of the deep dorsal vein of the penis using pulsed Doppler ultrasonography. Preliminary study].

OBJECTIVES AND METHODS: This was an open preliminary study of 36 unselected men suffering from erectile dysfunction (DE) for the evaluation of the deep dorsal vein of the penis (VDP) by duplex scan (EDP). All men had an intravenous injection (IIC) with a vaso active agent: alprostadil (Edex) (n = 24), a mixture of papaverine ifenprodyl tartrate (Vadilex) (n = 4) or papaverine, ifenprodyl tartrate and alprostadil (n = 7). The deep dorsal vein was evaluated, with a 13 mHz mechanical probe 5 and 10 minutes after the injection, during visual sexual stimulation (SSV) carried on for 10 mn, and 3 mn after having stopped SSV. The influence of deep breathing and contraction of the ischio and bulbo-cavernous muscles was recorded at each of the periods. RESULTS: The deep dorsal vein was identified in all cases. After pharmacological stimulation flow was present in 61% of the cases, with a statistically significant difference between alprostadil (80%) and both mixtures (20%). The addition of sexual stimulation caused flow to disappear in 64% of the cases (91% for the mixture and 44% for alprostadil). There was a range of variation under breathing and muscular contraction which deserves further evaluation. CONCLUSIONS: 1) The deep dorsal vein is easily studied under duplex scan and should be part of the routine examination of the vascular component of erection during erectile dysfunction. 2) The vein is subjected to modification of flow after intracavernous injection and sexual stimulation which varies with the agent injected and the clinical condition of the patients. 3) Absent flow early after injection seems to be predictive of the possibility of a prolonged erection.

Adult↗
PubMed1996

Intraoperative monitoring with pulse Doppler ultrasonography in transsphenoidal surgery: technique application.

We describe an intraoperative use of pulse Doppler ultrasonography in transsphenoidal surgery to prevent mechanical vascular injury, particularly to the intracavernous portion of the internal carotid artery. This system is integrated by connection to a video processor. The use of Doppler sonography provided real-time measurement of arterial or venous flow velocity and source of flow by both real-time sonograms and sound frequencies. With the use of a microprobe, 1 mm in diameter, vessels located within 7 mm from the tip of the probe could be easily, rapidly, and noninvasively detected, without disturbing operative field. Furthermore, both the size and the distance of a vessel could be measured by turning the dial of Doppler signal gain from initially waxing to waning Doppler sounds, because the acoustic sounds were adjusted to the axial flow of each vessel in 0.1-mm increments. Our intraoperative monitoring enhanced operative safety with technical simplicity and reliability.

Adenoma↗
PubMedDate not supplied

Prediction of brain blood flow using pulsed Doppler ultrasonography in newborn lambs.

The purpose of this study was to evaluate the ability of pulsed Doppler ultrasonography to predict brain blood flow by comparing measurements made in basal cerebral arteries using a pulsed Doppler system with measurements of brain blood flow using radioactive microspheres in lambs. We measured the instantaneous maximum velocity during peak systole and end diastole and the mean velocity over the pulse cycle in basal cerebral arteries, calculated Pourcelot's index of resistance and Gosling's pulsatility index, and used regression analysis to compare the pulsed Doppler measurements with brain blood flow measured with radioactive microspheres. Pulsed Doppler measurements of the peak systolic, end diastolic, and mean flow velocity in basal cerebral arteries were directly related to brain blood flow. In contrast, no linear relationship was detected between the resistance or pulsatility indices and brain blood flow measured by microspheres (p greater than 0.14). Prediction of brain blood flow for individual subjects lacks the quantitative precision necessary for use as a clinical tool. However, the direct relationship between brain blood flow and the peak systolic, end diastolic, and mean flow velocities in basal cerebral arteries supports the use of these measurements in clinical research for the qualitative assessment of change in brain blood flow.

Animals↗
PubMed1992

Estimation of blood flow in the carotid artery and intraorbital ophthalmic artery by color pulse Doppler ultrasonography.

Blood flow velocity was estimated in the orbital part of the ophthalmic artery and in the carotid artery, by way of pulse Doppler ultrasonography. The equipment was a Toshiba SSA-270A machine. The material comprised 12 glaucoma patients (20 eyes, all with open angles) under satisfactory IOP control, mean age 52 years, and 28 healthy controls (mean age 40 years; 54 eyes). Systolic flow velocities of 46 cm/sec and 103 cm/sec, in the ophthalmic and carotid artery respectively, were found in the normal subjects. With mean values of 42 and 116 cm/sec in the glaucoma group there was no significant difference between groups. The same applied to the average flow velocities. A considerable interindividual variation was found.

Adult↗
PubMed2002

Assessment of blood flow velocity waveforms of the pulmonary circulation by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography.

OBJECTIVE: To assess (1) pulmonary artery and peripheral pulmonary blood flow by using a multigate spectral Doppler system and standard pulsed color Doppler ultrasonography and (2) the reproducibility of peripheral pulmonary artery blood flow velocity waveforms. METHODS: Thirty-three women were enrolled in the study Fetal pulmonary artery flow velocity waveforms were investigated by multigate spectral Doppler scanning and traditional pulsed Doppler ultrasonography plus color flow mapping. To establish the relationship between these 2 methods, we calculated the correlation coefficient, coefficient of variation, and limits of agreement. RESULTS: The 2 methods were not significantly correlated. The range of measurement agreement for these 2 methods suggests that there is a significant difference between the main and peripheral pulmonary artery blood flow, and the difference should be taken into account in the interpretation of Doppler flow velocity studies of the pulmonary artery. CONCLUSIONS: Multigate spectral Doppler scanning with power Doppler imaging may be a better way to assess the average flow impedance in a highly vascularized organ. This technique supplies a large number of Doppler signals in the region of interest and offers a quantified range of Doppler measurements, improving our understanding of fetal hemodynamics.

Blood Flow Velocity↗