Three dimensional ultrasound elasticity imaging

Abstract

The aim of our work is to develop and evaluate an ultrasound (US) technique to quantitatively measure and image the shear modulus of soft tissues in three dimensions (3D). It is widely recognized that breast tissue pathologies, such as neoplasia, often alter biomechanical properties. Thus, the intended application of our work is the detection and characterization of breast tissue lesions, via elastic modulus imaging, to improve the specificity of breast cancer screening. To that end, we have designed and characterized algorithms which 1) provide 3-D motion estimates from 3-D US images and 2) solve the 3-D inverse problem to recover shear elastic modulus. The size and contrast accuracy of the reconstructed modulus distributions in tissue mimicking phantoms are presented. Inclusions as small as 5mm, some with contrasts marginally above unity, were successfully and clearly reconstructed. The effect of the boundary conditions and regularization methods on the reconstructed modulus images and the uniqueness of the solution are also discussed. In addition, preliminary modulus reconstructions created from clinical 3-D US breast images acquired in a mammography mimicking system are presented.