Tissue elasticity reconstruction based on ultrasonic strain measurements

Soft tissue elasticity are usually correlated to some abnormal process. Tissue displacement caused by an externally applied mechanical source or by the primary cardiac pulsation has been evaluated to characterize tissue elasticity. Quantitative elasticity imaging consists of measurement of tissue displacements, estimation of strain tensor components, and then reconstruction of elastic modulus based on strain fields. Here, a correlation-based speckle tracking algorithm was used to measure displacements, and the strain components was computed from displacement distribution, from which the relative shear modulus was reconstructed by solving the static equilibrium equation. The authors have applied the method to images of an inhomogeneous gelatin phantom. The spatial dependence of the strain tensors and the relative shear modulus shows good agreement with theoretically predicted values of a piecewise linear elastic model. The method has been also applied to liver in vivo to characterize the elasticity