Utilising non-linear elasticity to increase mechanical contrast in quantitative optical coherence elastography (Conference Presentation)

Abstract

Compression optical coherence elastography (OCE) enables rapid acquisition with high resolution over fields of view relevant to many clinical applications. Compression OCE typically provides a relative measure of mechanical properties; however, we have recently demonstrated a technique which quantifies stiffness via a compliant layer, termed quantitative OCE. In quantitative OCE, stiffness is reported as a tangent modulus, which is a surrogate for Young’s modulus at a given preload in non-linear elastic material. In biological tissues, which are typically non-linear elastic, values of stiffness reported through quantitative OCE could be over- or under-estimated, and are heavily biased by the arbitrary bulk preload applied to that region. We present a method to measure tissue nonlinearity locally, by preforming compression OCE at multiple preloads ranging from 2% to 40%. We show, through presentation of 2D quantitative elastograms, that compression OCE has the potential to measure the non-linear stiffness in tissue mimicking phantoms and biological tissue. Further, intrinsic mechanical contrast in tissue is dependent upon its preload. By tailoring tissue preload, we demonstrate improved contrast between benign and tumor tissue in a murine liver carcinoma model.