Model-based assessment of dynamic arterial blood volume flow from ultrasound measurements

Abstract

To assess in clinical practice arterial blood volume flow (BVF) from ultrasound measurements, the assumption is commonly made that the velocity profile can be approximated by a quasi-static Poiseuille model. However, pulsatile flow behaviour is more accurately described by a Womersley model. No clinical studies have addressed the consequences on the estimated dynamics of the BVF when Poiseuille rather than Womersley models are used. The aim of this study is to determine the influence of assumed Poiseuille profile instead of Womersley profile on the estimation and intrasubject variability of dynamical parameters of the BVF. For this purpose, a low number of volunteers sufficed. Brachial artery centerline velocity waveform and vessel diameter were measured with ultrasound within a small group of six volunteers. Within subjects, the intra-and inter-registration variability of BVF parameters estimates did not significantly differ. Poiseuille profiles compared to Womersley underestimates the maximum BVF by 19%, the maximum retrograde volume flow by 32% and the rise time by 18%. It can be concluded that when estimating in a straight vessel the dynamic properties of the BVF, Womersley profiles should preferably be chosen.

Errors in the estimation of wall shear stress by maximum Doppler velocity

“…Numerous MRI methods have been proposed and we refer to Petersson et al [5] for details. Measuring near-wall velocities with commercial Doppler ultrasound is very challenging and subject to error [31, 32]. Hence, specialised multi-gate Doppler systems have been designed to optimise the near-wall measurements [33, 34] or to improve assessment of skewed velocity profiles [35]; however these state-of-the-art systems are not widely available.…”

Metric field construction for anisotropic mesh adaptation with application to blood flow simulations

“…Because no information about the real flow condition was available for this geometry, an analytical model for the velocity profile was chosen to imitate cardiac cycles. Womersley profile is an appropriate description of the pulsatile flow behavior in fixed wall arterial geometries, as confirmed by C. A. D. Leguy et al, for example, [30]. Therefore, the mathematical formulation introduced by J. R. Womersley [31] is used in our simulations.…”

The Effect of Continuous Positive Airway Pressure on Total Cerebral Blood Flow in 23 Healthy Awake Volunteers

“…To calculate total CBF, it was assumed that zero phase delay occurred between the arrival of the FV sys at the ICA and VA and that a parabolic velocity profile was present to determine the true flow rate within the vessels [14]. To minimize measurement error, the mean flow in each vessel was approximated using the average of three sequential diastolic and systolic FV and diameter measurements.…”

“…2) and total experimental CBF, CBF exp , was determined by the sum of the flow in the left and right ICAs and VAs assuming a parabolic velocity profile [14] (Eq. 3).…”