Optical coherence tomography imaging depth enhancement by superficial skin optical clearing

Non-invasive imaging of human skin and human skin tissues by optical coherence tomography (OCT) is a field exciting a great deal of interest especially in terms of day-to-day medical and biomedical diagnostics. We develop rapid scanning OCT system for non-invasive real-time imaging of topical skin tissues in vivo. We investigate the possibility of OCT image enhancement along the transcutaneous diffusion into the skin an optical clearing agent. Diffusion of optical clearing agents, e.g. such as glycerol, temporary increases transparency of topical skin tissues that allows for unrestricted sounding radiation permeating deeper into the skin. Increasing transparency of superficial skin tissues significantly improves depth of imaging, image contrast and spatial resolution. Thus, topical optical clearing of skin enable applying low power light source (0.5 - 0.2 mW) and achieve the probing depth up to 1.5 - 1.7 mm. Current approach is able providing images of superficial human blood vessels 0.2 - 1 mm in diameter that are not visible by conventional OCT at normal conditions. The presented results illustrate, for the first time of our knowledge, the images of topical skin vessels with 12 mu m spatial resolution before and after optical clearing.