Estimation of displacement vectors and strain tensors in elastography using angular insonifications

We describe a new method for estimating all the components of the tissue displacement vector following a quasi-static compression. The method uses displacements estimated from radiofrequency echo-signals along multiple ultrasound beam insonification directions. At each spatial location in the compressed medium, orthogonal tissue displacements in both the axial and lateral directions with respect to the direction of the applied compression are estimated using least squares solutions. The components of the corresponding normal and shear strain tensors are then estimated. Simulation and experimental results demonstrate the utility of this technique for the computation of the normal and shear strain tensors.