Experimental validation of uterine artery volume blood flow measurement by Doppler ultrasonography in pregnant sheep

Abstract

Objective To test the hypothesis that Doppler-derived (calculated)

Local delivery of VEGF adenovirus to the uterine artery increases vasorelaxation and uterine blood flow in the pregnant sheep

“…We measured UBF using ultrasonography, a noninvasive technique used to quantify UBF in normal human pregnancy 23,29 as well as those complicated by FGR. 24 Quantification of UBF using Doppler has recently been validated in the pregnant sheep in late gestation, and correlated well with direct measurement using implanted flow probes. 24 The measurements of UBF we obtained at 88-102 days of gestation in pregnant sheep were similar to those observed in pregnant humans (300-1000 ml min À1 ) in mid to late pregnancy.…”

“…24 Quantification of UBF using Doppler has recently been validated in the pregnant sheep in late gestation, and correlated well with direct measurement using implanted flow probes. 24 The measurements of UBF we obtained at 88-102 days of gestation in pregnant sheep were similar to those observed in pregnant humans (300-1000 ml min À1 ) in mid to late pregnancy. 23 Although Doppler measurements of volume blood flow are prone to inter-and intraobserver error, the increase in UBF that we observed after delivery of Ad.VEGF-A was reproducible, indicating that VEGF-A overexpression produced a biologically meaningful enhancement of blood flow 4-7 days postinjection.…”

“…The time-averaged maximum blood flow (TAMX-V) was measured in the uterine arteries (UtAs) according to standard methodology 2,12 and corrected for the velocity profile using a spatial velocity distribution coefficient derived in the sheep UtA. 24 The average value of three consecutive cardiac cycles was used for statistical analysis. The vessel diameter, D was measured during systole using color Doppler angiography three times and the average value was used to calculate the vessel area (A) assuming the vessel to have a circular lumen (A ¼ p(D/2) 2 ).…”

SPIO‐enhanced magnetic resonance imaging study of placental perfusion in a rat model of intrauterine growth restriction

“…1,2 Moreover, Doppler ultrasound cannot be routinely used to quantify placental perfusion, a parameter that could in theory be measured in millilitres of blood per gram of placenta per minute, even though several studies have measured uterine artery blood flow volume during pregnancy. [4][5][6][7] Several experimental approaches have been developed to assess placental function, including the use of radioactive microspheres and angiography, but their routine clinical use is severely restricted by concerns for both fetal and maternal safety. 8 Magnetic resonance imaging (MRI) is being increasingly used as a diagnostic tool in human pregnancy, and recent reports suggest that it may provide important information on placental function.…”

28: First trimester alcohol exposure alters placental perfusion and fetal oxygen availability affecting fetal growth and development in a non-human primate model

“…The lowest high-pass filter level was used (100 Hz), and an angle of 15° or less between the vessel and the Doppler beam was deemed acceptable. Blood flow velocity waveforms were obtained from the proximal portion of the uterine artery (Uta) as previously described [24][25][26] . Doppler waveform measurements for the Uta and umbilical artery were performed and averaged over three cycles using machine-specific software and the following measurements were obtained: pulsatility index (PI), velocity time integral (VTI), and fetal heart rate (HR) [24][25][26] .…”