Blood Flow Velocity Estimation from Ultrasound Speckle Tracking Using Chirp Signals
Ultrasound speckle tracking has been used to estimate the blood flow velocity, because this method can overcome the major limitation of the Doppler method: angle dependence and aliasing. The speckle tracking is based on the brightness of image pixels which always bring difficulty for dark flow areas due to the low reflectivity of blood cells. Therefore, the conventional speckle tracking method is sensitive to signal-to-noise ratio (SNR) of flow and its performance will be significantly deteriorated from existing ultrasound system noise. In this paper, we present a fast sum-absolute-difference (SAD) based speckle tracking method by using chirp signals instead of the conventional broadband signals to increase the flow SNR and investigate the detected errors for flow velocity estimation. Simulation results show that our method can improve the velocity estimation by 12% compared with basic broadband speckle tracking methods.