Mechanical compression in cross-polarization OCT imaging of skin: In vivo study and Monte Carlo simulation

Abstract Optical coherence tomography (OCT) is rapidly advancing into clinical practice beyond the area of ophthalmology. Many applications of OCT in areas such as dermatology, endoscopy and others require contact OCT probes which transfer compression to the studied tissues. This effect should be taken into account when developing methods for OCT diagnostics. On the other hand, controlled compression can provide additional diagnostic information and can serve as a diagnostic procedure. This paper discusses the effect of controlled mechanical compression induced by an OCT probe coupled with dynamometer on cross-polarization OCT images of skin. Registration of OCT images in two polarizations (parallel and orthogonal) allows additional information to be obtained about structural features of the studied tissue. An increase in contrast of epidermis/dermis junction and a decrease in contrast of stratum corneum/epidermis junction in OCT images are shown to originate from mechanical compression of human skin in vivo which could be associated with structural and functional changes induced by compression. In order to confirm the origin of the contrast in OCT images induced by mechanical compression, Monte Carlo simulations were performed; the results of which are in qualitative agreement with experimental results.