Ultrasonic strain imaging of the female breast using phase root seeking and three-dimensional “optical flow”

We implemented an ultrasonic strain imaging system to support the tissue characterization of the female breast. The breast is compressed between two plates of polyethylene and of steel, respectively. 3D elastographic raw data of the breast can be acquired. The displacement is estimated by finding the phase root of the cross-correlation between the pre- and post-compression complex base-band echoes. The estimation is enhanced by 3D “optical flow”: we estimate transversal (lateral and out of plane) displacement which is used to correct the axial trajectories in the post-compression image. In spite of the low signal-to-noise ratio of single compression elastograms, transversal displacements, and motion artifacts, encouraging strain images are obtained. We will demonstrate the performance of this technique by phantom and in vivo results