Recent advances in blood flow vector velocity imaging

Ultrasound Imaging Velocimetry: a review

“…A similar multiple-angle approach can also be implemented with a single array using beam-steering (Fadnes et al 2015). Another technique that was introduced is the transverse oscillation method (Jensen and Munk 1998;Jensen et al 2011). In this method the ultrasound pulse (as shown in e.g.…”

Doppler Modes

“…Also, the Doppler effect has a strong angular dependence (cos θ) as illustrated by Figure 11.1. Jensen (Evans, Jensen, & Nielsen, 2011;Jensen et al, 2011) has pointed out that laminar flow does not v beam 5 jvjcosθ 5 f D c 0 f 0 2 (11.36) (Evans et al, 2011). Imaging systems do not have the capability to anticipate the angle between the insonifying beam and the actual attitude of the vessel; therefore the angle correction is unlikely to be accurate.…”

“…Finally, the TO method was brought to a commercial scanner Jensen et al, 2011;. Practical advantages of implementing the TO approach are that the velocity information is derived from the same transmit beams and pulse sequence, and similar Hilbert transform and autocorrelation algorithms are used for both directions.…”

“…Previous methods for obtaining vector Doppler, which are more limited in their applicability, are reviewed in Evans et al (2011);Jensen et al (2011);Mace et al, (2013); and Udesen and Jensen (2006). These methods, which include synthetic aperture and plane-wave compounding, will be emphasized as well as a another one, transverse oscillation.…”

A PSF-Shape-Based Beamforming Strategy for Robust 2D Motion Estimation in Ultrafast Data

“…This allows for imaging at ultrafast frame rates in the kHz range. Hereby, decorrelation of speckle can be minimized and fast moving, sometimes short-lived, motion patterns can be tracked [28][29][30][31][32]. However, frame-to-frame tissue displacements become smaller, since they scale with the imaging frame rate.…”