Analysis of shear strain imaging for classifying breast masses

Different features derived from shear strain images of breast masses have been utilized to differentiate between benign and malignant breast masses. In particular the normalized axial-shear strain area feature has been utilized to provide improved discrimination performance under in-vivo imaging conditions. In this study we compare the shear strain patterns exhibited by both the full-shear and the axial-shear strain component. We examine different breast mass characteristics such as tumor shape, asymmetric location of masses, stiffness variations, and mass bonding characteristics to the background to assess the impact on shear strain imaging in differentiating benign from malignant tumors. Our results indicate that the normalized axial-shear strain and full-shear strain area features are larger for firmly bonded masses when compared to loosely bonded ones. A higher stiffness ratio or contrast between the inclusion and background also improves differentiation. Larger applied deformations reduce the discrimination performance for friction coefficients lower than 0.4. Potential errors with the use of this feature would occur for loosely bound inclusions at larger applied deformations and for asymmetric masses.