A real-time method for breast cancer diagnosis using optical flow

Most conventional methods of breast cancer diagnosis such as X-ray, Ultrasound (US) and MRI have some issues ranging from weaknesses associated with tumour detection or classification to high cost. In this study, we propose a breast elastography technique based on 3D US. This technique is fast, expected to be cost effective and more sensitive and specific compared to US imaging. Unlike current elastography techniques that image relative elastic modulus, this technique is capable of imaging absolute Young's modulus (YM). In this technique, tissue displacements and surface forces used to mechanically stimulate the tissue are acquired and used as input to reconstruct the tissue YM distribution. For the displacements acquisition, we use a modified optical flow technique to estimate the displacement of each node from 3D US pre- and post-compression images. A force sensor is used to measure forces on the surface of the breast. These forces are input into an analytical model to estimate tissue stress distribution. By combining the stress field with the strain field calculated from the estimated displacements using Hooke's law, the YM can be reconstructed efficiently. Also, we adapted a micromechanics based model developed for strain distribution estimation in heterogeneous medium to update the reconstructed YM value of tumor more accurately.