Implementation of a novel pulsed ultrasonic Doppler velocity profiler

2003 ◽  
Author(s):  
Shounan Luo ◽  
Yan Liu ◽  
Guanping Feng
Keyword(s):  
Doppler Velocity ◽  
Pulsed Ultrasonic

Pulsed Ultrasonic Doppler Velocity Measurements Inside a Left Ventricular Assist Device

1986 ◽  
Vol 108 (3) ◽  
pp. 232-238 ◽  
Author(s):  
J. M. Tarbell ◽  
J. P. Gunshinan ◽  
D. B. Geselowitz ◽  
G. Rosenberg ◽  
K. K. Shung ◽  
...  
Keyword(s):  
Ventricular Assist Device ◽  
Single Channel ◽  
Left Ventricular ◽  
Doppler Velocity ◽  
Shear Stresses ◽  
Reynolds Stresses ◽  
Assist Device ◽  
Data Set ◽  
Ventricular Assist ◽  
Pulsed Ultrasonic

In this study we have employed a single channel, pulsed ultrasonic Doppler velocimeter to measure instantaneous velocity distributions within the pumping chamber of a ventricular assist device. Instantaneous velocities have been decomposed into periodic mean and turbulent fluctuating components from which estimates of Reynolds stresses within the chamber and mean shear stresses along the wall of the chamber have been obtained. A review of the complete data set indicates a maximum value of the mean wall shear stress of 25 dynes/cm2 and a maximum Reynolds stress of 212 dynes/cm2. These values are lower than those measured distal to aortic valve prostheses in vitro and are well below levels known to damage blood components. Core flow patterns, wall washing patterns and flow stagnation points are also revealed.

Venous ultrasound catheter-tip technique for evaluation of arterial hemodynamics

1976 ◽  
Vol 41 (6) ◽  
pp. 946-952 ◽  
Author(s):  
R. C. Nealeigh ◽  
C. W. Miller ◽  
F. D. McLeod
Keyword(s):  
Wall Motion ◽  
Arterial Wall ◽  
Evaluation Studies ◽  
Doppler Velocity ◽  
Flow Properties ◽  
Iliac Arteries ◽  
Arterial Hemodynamics ◽  
Velocity Flow ◽  
Catheter Tip ◽  
Pulsed Ultrasonic

A variety of devices has been used for measuring flow properties of deep-lying arteries, but many have limitations. This paper describes a relatively nontraumatic intravenous approach which uses a catheter in connection with a pulsed ultrasonic Doppler velocity meter (PUDVM) and an ultrasound echo track. The venous ultrasound catheter (VUC) has permitted measurements oflocal instantaneols blood velocity, flow, and wall motion in the abdominal aorta and iliac arteries of beagle dogs; evaluation studies have been conducted to compare the VUC recordings with an independent method for measuringblood flow and wall motion. Coupling of this catheter-tip device with the PUDVM and echo track provides chronic measurements of hemodynamic parametersin these deep vessels which were virtually impossible to obtain previously.This technique may prove useful in monitoring vessel pathology longitudinally as well as in basic experimental situations requiring flow and arterial wall mechanical properties.

scholarly journals The role of sildenafil citrate in the treatment of fetal growth restriction: a randomized controlled trial

2019 ◽  
Vol 8 (5) ◽  
pp. 1840
Author(s):  
Ahmed Abdelshafy ◽  
Khaled Ibrahim Abdullah ◽  
Sherif Ashoush ◽  
Heba E. Hosni
Keyword(s):  
Middle Cerebral Artery ◽  
Fetal Growth ◽  
Cerebral Artery ◽  
Fetal Growth Restriction ◽  
Umbilical Artery ◽  
Controlled Trial ◽  
Maternity Hospital ◽  
Growth Restriction ◽  
Sildenafil Citrate ◽  
Doppler Velocity

Background: This study was aimed to evaluate the effect of sildenafil citrate on Doppler velocity indices in patients with fetal growth restriction (FGR) associated with impaired placental circulation.Methods: A double-blinded, parallel group randomized clinical trial (clinicaltrials.gov NCT02590536) was conducted in Ain Shams Maternity Hospital, in the period between October 2015 and June 2017. Ninety pregnant women with documented intrauterine growth retardation at 24-37 weeks of gestation were randomized to either sildenafil citrate 25 mg orally every 8 hours or placebo visually-identical placebo tablets with the same regimen. The primary outcome of the study was the change in umbilical artery and fetal middle cerebral artery indices.Results: There was a significant improvement in umbilical and middle cerebral artery indices after sildenafil administration p<0.001. Present study observed that, sildenafil group, in comparison to placebo, has a significantly higher mean neonatal birth weight. 1783±241g vs 1570±455g (p<0.001). There was a significantly higher mean gestational age at delivery in women in sildenafil group 35.3±1.67 weeks, whereas it was lower in the placebo group 33.5±1.7 weeks. The side effects as headache, palpitation and facial flushing were significantly higher in sildenafil group compared to placebo group.Conclusions: The use sildenafil citrate in pregnancies with fetal growth restriction (FGR) improved the feto-placental Doppler indices (pulsatility index of umbilical artery and middle cerebral artery) and improved neonatal outcomes.

scholarly journals A computational model-based approach for atlas construction of aortic Doppler velocity profiles for segmentation purposes

2018 ◽  
Vol 40 ◽  
pp. 23-32 ◽  
Author(s):  
Vedrana Baličević ◽  
Hrvoje Kalinić ◽  
Sven Lončarić ◽  
Maja Čikeš ◽  
Bart Bijnens
Keyword(s):  
Computational Model ◽  
Velocity Profiles ◽  
Doppler Velocity ◽  
Model Based ◽  
Atlas Construction
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