Assessment of human breast cancer margins by compressional optical coherence elastography

Abstract

This study presents results on application of compressional optical coherence elastography (OCE) for visualization of a transitional zone between peri-tumoral (normal) and tumor region of breast tissue. The assessment of non-tumor/tumor regions is made based on percentage of pixels with different characteristic stiffness (“stiffness spectrum”) in the OCE image, also taking into account spatial localization of different-stiffness regions. The OCE-based stiffness maps and corresponding histograms of normalized stiffness spectrum demonstrate clear the boundary between normal (peritumoral) tissue and an invasive tumor. The normal breast tissue is fairly heterogeneous on the OCE images with increased stiffness in the region of the lobular structures and lower stiffness in the surrounded soft fibrous and especially adipose tissue of the mammary gland. The invasive breast cancer includes mechanically more dense stiffer accumulations of tumor cells, as well as less stiffer hyalinized tumor stroma. The corresponding histograms of stiffness show clearly dominating and ever increasing percentage of stiff regions in the tumor tissue showing gradually diminishing share of the normal stromal component in tissue. Thus, analysis of the so-obtained normalized histograms (“stiffness spectrum”) may be used to assess the negative surgical margin of resection in the future.