Monogenic orientation-based blood flow estimation in high-frequency ultrasound imaging

Classical blood flow estimation techniques are based on the Doppler effect, but suffer from several limitations: inadequate estimations of low velocities, limited spatial resolution and impossibility to estimate flows perpendicular to the beam axis. In a recent work, the velocity was related to the texture orientation in spatiotemporal planes extracted from an ultrasound 2D+t volume. This texture orientation was previously estimated using a bank of orientated Gabor filters. This represents one of the major drawbacks of this method, as the accuracy of the estimates is directly linked to the angular step between two consecutive filters. We propose a novel velocity estimation method, based on the same assumption that a moving target leaves a trace in the spatio-temporal plane, generating an orientation of the texture related to its velocity. In our approach, we propose to estimate this orientation using the framework of the monogenic signal and thus to avoid the large amount of Gabor filters classically used.