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Giancarlo Mari - One of the best experts on this subject based on the ideXlab platform.
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Assessment of blood flow velocity waveforms of the pulmonary circulation by multigate spectral Doppler scanning and traditional Pulsed Doppler Ultrasonography.
Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 2002Co-Authors: Ren Ing Liang, Nikos Prapas, Laura Detti, Erich Cosmi, Joshua A. Copel, Giancarlo MariAbstract: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.
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Assessment of Doppler velocimetry of the fetal umbilical artery by multigate spectral Doppler scanning and traditional Pulsed Doppler Ultrasonography plus color flow mapping.
Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine, 1999Co-Authors: N. Prapas, Ren Ing Liang, Giancarlo Mari, Joshua A. CopelAbstract: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.
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Doppler flow velocimetry of the splenic artery in the human fetus is it a marker of chronic hypoxia
American Journal of Obstetrics and Gynecology, 1995Co-Authors: Alfred Abuhamad, Giancarlo Mari, Donna Bogdan, Arthur T EvansAbstract:Abstract OBJECTIVE: The aim of this investigation was to describe splenic artery flow velocity waveforms in the appropriate- and small-for-gestational-age human fetus. STUDY DESIGN: Splenic artery flow velocity waveforms were prospectively obtained from 95 appropriate- and 15 small-for-gestational-age fetuses with Pulsed Doppler Ultrasonography. The resistance index was used to quantify the Doppler waveform. RESULTS: A second-degree polynomial model expressed the changes of the resistance index in appropriate-for-gestational-age fetuses with advancing gestation ( y = 0.057 x [Weeks] - 0.001 x 2 , r = 0.53, p CONCLUSION: Our results suggest that some small-for-gestational-age fetuses have decreased resistance at the level of the splenic artery. We postulate that the increased erythropoietin level, stimulated by hypoxia, results in decreased resistance at the level of the splenic artery in small-for-gestational-age fetuses. Finally, management of the small-for-gestational-age fetus may be aided by the study of the splenic artery waveforms.
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Doppler assessment of renal blood flow velocity waveforms in the anemic fetus before and after intravascular transfusion for severe red cell alloimmunization.
Journal of clinical ultrasound : JCU, 1991Co-Authors: Giancarlo Mari, Kenneth J. Moise, Russell L. Deter, Robert J. CarpenterAbstract:Image-directed Pulsed Doppler Ultrasonography demonstrated a decrease in the pulsatility index of the renal artery in 9 anemic fetuses (less than 30 weeks, menstrual age) soon after intravascular transfusion. The pulsatility index returned to pretransfusion values the day following the transfusion. End diastolic blood velocity in the renal artery could not be measured before the transfusion, was detectable immediately after the procedure, and was again nonmeasurable one day after the transfusion. These data suggest an increase in renal blood flow in the anemic fetus soon after intravascular transfusion to eliminate excess fluid.
Giuseppe Rizzo - One of the best experts on this subject based on the ideXlab platform.
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Prenatal diagnosis of gastroesophageal reflux by color and Pulsed Doppler Ultrasonography in a case of congenital pyloric atresia.
Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology, 1995Co-Authors: Giuseppe Rizzo, Domenico Arduini, Alessandra Capponi, C. RomaniniAbstract: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.
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Effects of maternal hyperoxygenation on ductus venosus flow velocity waveforms in normal third-trimester fetuses.
Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology, 1993Co-Authors: M. Soregaroli, Giuseppe Rizzo, L. Danti, Domenico Arduini, C. RomaniniAbstract:On the basis of the data obtained in sheep fetuses showing a high interdependence between umbilical vein oxygenation and ductus venosus flow, we investigated the effect of maternal hyperoxygenation on ductus venosus velocity waveforms in normal third-trimester human fetuses. Ductus venosus velocity waveforms were recorded by using color and Pulsed Doppler Ultrasonography before and after 15 min of maternal administration of humidified 60% oxygen. During maternal hyperoxygenation, there was a significant increase of both estimated peak velocities during systole, diastole and atrial contraction and the mean temporal velocity during the total cardiac cycle and systolic and diastolic portions. On the other hand, during maternal hyperoxygenation, no significant changes were found in fetal heart rate or in the ratios between peak velocities and mean temporal velocities during systole and diastole. These findings suggest a close relationship between fetal oxygenation and ductus venosus velocity waveforms that may be useful in monitoring fetal hypoxemia. Copyright © 1993 International Society of Ultrasound in Obstetrics and Gynecology
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Umbilical vein pulsations: a physiologic finding in early gestation.
American Journal of Obstetrics and Gynecology, 1992Co-Authors: Giuseppe Rizzo, Domenico Arduini, Carlo RomaniniAbstract:OBJECTIVES: The purpose of this study was to establish the incidence of umbilical vein pulsations in normal early pregnancies and to evaluate whether these pulsations are related to Doppler-measured vascular resistances in umbilical artery or central venous flow patterns. STUDY DESIGN: We performed a cross-sectional study on 257 uneventful pregnancies at 7 to 16 weeks of gestation by means of transvaginal color and Pulsed Doppler Ultrasonography. Blood flow velocity waveforms were recorded from the umbilical artery, umbilical vein and, in 48 cases, also from fetal inferior vena cava. RESULTS: Pulsations in the umbilical vein were evidenced in all cases until 8 weeks. From this gestational age on pulsations progressively disappeared, becoming completely absent at ≥13 weeks. The incidence of pulsations in the umbilical vein was unrelated to umbilical artery pulsatility index values, the incidence of absent end-diastolic flow in umbilical artery, and fetal heart rate. In the inferior vena cava, reverse flow during atrial contraction was significantly higher ( p ≤ 0.002) in cases with umbilical vein pulsations than in those cases without pulsations at a similar gestational age. CONCLUSIONS: Pulsations in the umbilical vein are physiologically present during the first trimester of pregnancy and seem to be related to inferior vena cava flow patterns.
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Umbilical artery velocity waveforms in early pregnancy: a transvaginal color Doppler study.
Journal of clinical ultrasound : JCU, 1991Co-Authors: Domenico Arduini, Giuseppe RizzoAbstract:In a cross-sectional study, umbilical artery velocity waveforms were recorded in 214 low-risk pregnancies at 7 weeks to 16 weeks, menstrual age, by means of transvaginal color and Pulsed Doppler Ultrasonography. In all the cases studied, end diastolic velocities were absent until the 10th week. From this age onward end diastolic velocities were present in a percentage of pregnancies, progressively increasing with gestation and reaching 100% at 15 weeks. Similarly, the percentage of cardiac cycles in which end diastolic velocities were absent progressively decreased with advancing menstrual age. The normal range for the pulsatility index was constructed and a quadratic function was found to optimally fit its fall during gestation. No differences in pulsatility index values were found at these menstrual ages in 12 pregnancies that later developed intrauterine growth retardation and/or pregnancy-induced hypertension, suggesting that placental alterations causing abnormalities in umbilical velocity waveforms occur later in gestation.
Jean-jacques Eledjam - One of the best experts on this subject based on the ideXlab platform.
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Pulsed Doppler Ultrasonography guidance for catheterization of the subclavian vein: a randomized study.
Anesthesiology, 1998Co-Authors: Jean Yves Lefrant, Philippe Cuvillon, J. F. Benezet, Michel Dauzat, Pascale Peray, Gilbert Saissi, Jean-emmanuel De La Coussaye, Jean-jacques EledjamAbstract:BackgroundCatheterization 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.MethodsStandard and Doppler Ultrasonography guidance methods wer
Carlo Romanini - One of the best experts on this subject based on the ideXlab platform.
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Umbilical vein pulsations: a physiologic finding in early gestation.
American Journal of Obstetrics and Gynecology, 1992Co-Authors: Giuseppe Rizzo, Domenico Arduini, Carlo RomaniniAbstract:OBJECTIVES: The purpose of this study was to establish the incidence of umbilical vein pulsations in normal early pregnancies and to evaluate whether these pulsations are related to Doppler-measured vascular resistances in umbilical artery or central venous flow patterns. STUDY DESIGN: We performed a cross-sectional study on 257 uneventful pregnancies at 7 to 16 weeks of gestation by means of transvaginal color and Pulsed Doppler Ultrasonography. Blood flow velocity waveforms were recorded from the umbilical artery, umbilical vein and, in 48 cases, also from fetal inferior vena cava. RESULTS: Pulsations in the umbilical vein were evidenced in all cases until 8 weeks. From this gestational age on pulsations progressively disappeared, becoming completely absent at ≥13 weeks. The incidence of pulsations in the umbilical vein was unrelated to umbilical artery pulsatility index values, the incidence of absent end-diastolic flow in umbilical artery, and fetal heart rate. In the inferior vena cava, reverse flow during atrial contraction was significantly higher ( p ≤ 0.002) in cases with umbilical vein pulsations than in those cases without pulsations at a similar gestational age. CONCLUSIONS: Pulsations in the umbilical vein are physiologically present during the first trimester of pregnancy and seem to be related to inferior vena cava flow patterns.
Yasuki Higaki - One of the best experts on this subject based on the ideXlab platform.
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Effect of exercise intensity on renal blood flow in patients with chronic kidney disease stage 2
Clinical and Experimental Nephrology, 2019Co-Authors: Kazuko Kotoku, Tetsuhiko Yasuno, Shotaro Kawakami, Kanta Fujimi, Takuro Matsuda, Shihoko Nakashima, Yoshinari Uehara, Hiroaki Tanaka, Takao Saito, Yasuki HigakiAbstract:Background Acute exercise reduces renal blood flow (RBF). However, the effect of exercise intensity on RBF in patients with chronic kidney disease (CKD) stage 2 is not known. We investigated the association between RBF and exercise intensity in patients with CKD stage 2 using Pulsed Doppler Ultrasonography. Methods Eight men with CKD stage 2 (cystatin C-based estimate of glomerular filtration rate: 60–89 ml/min/1.73 m^2) participated in this study. Using a bicycle ergometer, participants undertook a maximal graded exercise test (MGET) (experiment 1) and a multi-stage exercise test (experiment 2) to determine their lactate threshold (LT). Participants undertook a multi-stage exercise test for 4-min each. Workloads of 60%, 80%, 100%, 120%, and 140% of LT were used in experiment 3. RBF was measured by Pulsed Doppler Ultrasonography at rest, immediately after exercise, and 1 h after exercise in experiment 1, and at rest and immediately after each exercise bout in experiment 3. Results Renal blood flow after the MGET was 52% lower than at rest, and did not recover as well as after the exercise test. Cross-sectional area (CSA) was significantly lower after graded exercise. RBF tended to be lower at 100% of LT and was significantly lower at 120% of LT. CSA was significantly lower at 100% of LT. Conclusions Renal blood flow does not change during exercise until the LT is reached. These findings may assist in making appropriate exercise recommendations to patients with CKD stage 2.
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Effect of exercise intensity on renal blood flow in patients with chronic kidney disease stage 2.
Clinical and experimental nephrology, 2019Co-Authors: Kazuko Kotoku, Tetsuhiko Yasuno, Shotaro Kawakami, Kanta Fujimi, Takuro Matsuda, Shihoko Nakashima, Yoshinari Uehara, Hiroaki Tanaka, Takao Saito, Yasuki HigakiAbstract:Acute exercise reduces renal blood flow (RBF). However, the effect of exercise intensity on RBF in patients with chronic kidney disease (CKD) stage 2 is not known. We investigated the association between RBF and exercise intensity in patients with CKD stage 2 using Pulsed Doppler Ultrasonography. Eight men with CKD stage 2 (cystatin C-based estimate of glomerular filtration rate: 60–89 ml/min/1.73 m2) participated in this study. Using a bicycle ergometer, participants undertook a maximal graded exercise test (MGET) (experiment 1) and a multi-stage exercise test (experiment 2) to determine their lactate threshold (LT). Participants undertook a multi-stage exercise test for 4-min each. Workloads of 60%, 80%, 100%, 120%, and 140% of LT were used in experiment 3. RBF was measured by Pulsed Doppler Ultrasonography at rest, immediately after exercise, and 1 h after exercise in experiment 1, and at rest and immediately after each exercise bout in experiment 3. Renal blood flow after the MGET was 52% lower than at rest, and did not recover as well as after the exercise test. Cross-sectional area (CSA) was significantly lower after graded exercise. RBF tended to be lower at 100% of LT and was significantly lower at 120% of LT. CSA was significantly lower at 100% of LT. Renal blood flow does not change during exercise until the LT is reached. These findings may assist in making appropriate exercise recommendations to patients with CKD stage 2.
