Correlation-based Doppler-angle estimation with plane-wave excitation

Abstract

Conventional Doppler imaging does not provide angle information, which makes it difficult to obtain flow information, especially for lateral flows. A correlation-based transit-time approach has been developed for estimating the Doppler angle under the framework of a focused-beam architecture, which has a fast computation capability. However, there is still a trade-off between the estimation accuracy and data acquisition time, and so this study applied plane-wave excitation with the aim of mitigating this limitation. In addition, three Doppler-angle estimation methods based on (1) the fast Fourier transform, (2) correlation, and (3) an autoregressive model were used to estimate Doppler angles. The estimation performances and computation loads of the three approaches were compared using simulations and a flow phantom. The simulation results showed that the Doppler angle can be correctly estimated with a sufficient aspect ratio, and Doppler-angle estimation using plane-wave excitation outperformed the focused-beam method. The flow-phantom experiments revealed the minimum number of ensembles required for the different approaches. The velocity-vector profiles were also demonstrated using the correlation and autoregressive methods, to show the feasibility of both lateral and axial velocity estimation using the proposed methods.

Keywords

• Autoregressive model
• Correlation
• Doppler-angle estimation
• Plane-wave excitation
• Transit-time Doppler bandwidth estimation