Sub-micron tissue motion estimation for high framerate ultrasound using complex gradient optimization

Here, a complex gradient optimization approach for precise estimation and correction of tissue motion in ultrasound data is introduced. The concept is to use gradient descent optimization to minimize the magnitude of the complex difference between neighboring frames in an ultrasound sequence. This method outperforms transverse-oscillation, speckle tracking, intensity registration-based methods for precise motion estimation in both in vivo and simulated ultrasound datasets, with sub-micron motion estimation accuracy shown in simulated data. Used with echo-cancellation in vivo for ultrasound rat data, peak tissue amplitude was reduced by a further 11 dB compared to prior motion estimation and correction methods.