Abstract
Dynamic Optical Coherence Straingraphy (D-OCSA) can visualize tomographically and non-invasively strain rate tensor distribution in biological tissue at the micro scale, using tomographic images consecutively captured by Optical Coherence Tomography (OCT) with tissue deformation. D-OCSA can time-continuously provide the accurate displacement vector distribution, by recursively applying the speckle cross-correlation method as well as the high accurate subpixel analysis of upwind gradient method and image deformation method. In this study, D-OCSA was ex vivo applied to degenerative articular cartilage by enzyme treatment with compression test, so as to evaluate space and time dependent bio-mechanical behaviors. Consequently, D-OCSA can discover compressive strain rate concentrated locally on the surface zone. These observations are thought to be generated by depth-dependent viscoelastic properties, which is related with the inhomogeneous and anisotropic matrix network composed of collagen fibers and proteoglycans with water. It was concluded that D-OCSA is biomedically effective as a directly diagnosing technique of micro-biomechanics, such as clinically diagnosis of osteoarthritis.
