A novel in vivo procedure for volumetric flow measurements

Characterizing momentum change and viscous loss of a hemodynamic endpoint in assessment of coronary lesions

“…To estimatec hÀg , mean coronary flow is needed. Many studies have validated the use of Doppler flow wire to measureQ with reasonable accuracy both in vivo and in vitro, especially at hyperemia (Doriot et al, 2000;Doucette et al, 1992;Jenni et al, 2000Jenni et al, , 2004Webb et al, 2005). Recently, a single wire with pressure and Doppler flow sensor has been used for simultaneous measurement of Dp andQ (Siebes et al, 2004).…”

Womersley Number-Based Estimates of Blood Flow Rate in Doppler Analysis: In Vivo Validation by Means of Phase-Contrast MRI

“…At any instant along the cardiac cycle, the shape of the spatial velocity profile is not known a priori (see, e.g., [23] and [24]). Indeed, it is known that, despite the validity of the cylindrical symmetry hypothesis, the shape of the velocity profile is influenced by many factors, including pulsatility, viscosity, and diameter in vascular districts (see [33], [48], and [56]).…”

Womersley number-based estimation of flow rate with Doppler ultrasound: Sensitivity analysis and first clinical application

“…It is worth stressing that the a priori assumption of spatial velocity profile (usually a parabolic one) required by the single-point Doppler method introduces a bias in any flow rate estimate with potentially remarkable consequences. For what concerns the mean flow rate, even if some authors supported using a parabolic velocity profile (see [6,29]), in more recent years this has been considered too simplistic and misleading (see [43,21,22]). The limitations obtained by estimating the peak flow rate by using a parabolic velocity profile have been pointed out in [40] where a mathematically more sophisticated approach has been proposed.…”