3-D Numerical Modeling of Breast Biomechanics during Ultrasound Elastography

Ultrasound-based elastography imaging is a popular method for characterizing tumors, based on the fact that cancers are stiff. Ultrasound radio frequency data is recorded using either external compression or quasi-static compression with a hold. This data is used to estimate local strains using motion tracking algorithms. No standard strategy is employed to maximize strain diagnostic contrast, leading to low or absent image contrast with small-deep (\u3c1cm) tumors. Here, finite element models using three-dimensional computer-aided designs of breast and tumor tissues are used to investigate strain image contrast by estimating local stresses and strains for static and quasi-static stimuli. Results show that local strain contrast increases with tumor stiffness and applied force, but almost plateaus for very stiff deep tumors. However, local stresses concentrate significantly in deep regions. Quasi-static measurements display increased local strain amplitude and can potentially offer a higher strain contrast for deep tumors