Advances in Tissue Elasticity Reconstruction Using Linear Perturbation Method

Abstract

Elastography, recently proposed by Ophir et al.,1 is a promising new acoustic imaging modality for tissue characterization. For example, it was proposed to use such technique for breast cancer detection on the basis of tissue hardness being indicative of the presence of tumor, as the practice of palpation examination indicates2. With this modality, tissue elastic properties are revealed through assessments of tissue displacements induced by a small external quasi static compression; specifically, the pre- and post-compression radio frequency (RF) ultrasound signals are used to estimate the axial tissue displacement and the associated strain component. Under the assumption of a constant stress-field, the strain-field can be interpreted as a relative measure of elasticity distribution; the strain being large in compliant (i.e. soft) tissue and small in a rigid (hard) one. This strain field visualized as a gray level image is termed an elastogram.1