Optical coherence tomography imaging depth enhancement by superficial skin optical clearing

Abstract

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 µm spatial resolution before and after optical clearing.OCT image (2 × 2 mm) of subcutaneous blood vessel in human skin in vivo after 20 minutes of optical clearing

Accessing to arteriovenous blood flow dynamics response using combined laser speckle contrast imaging and skin optical clearing

“…Finally, the LSCI can be applied to obtain better image quality for monitoring the cutaneous microcirculation. However, the similar improvement in blood vessels imaging using OCT could be not found at application of glycerol as an OCA [64][65][66]. The main reasons may be from the two aspects: firstly, thiazone, as a chemical penetration agent, was used in our work, could significantly enhance the skin optical clearing efficacy [39][40][41], as well as the penetration of glycerol into skin sample is relatively limited [29,67,68].…”

“…Thus, dynamic speckle signals can be detected easily through the transparent skin. Previous investigation indicated that increasing transparency of skin could significantly improves depth of imaging, image contrast and spatial resolution [64]. Finally, the LSCI can be applied to obtain better image quality for monitoring the cutaneous microcirculation.…”

Collaborative effects of wavefront shaping and optical clearing agent in optical coherence tomography

“…In fact, various mechanisms are involved, such as the dissociation of collagen 15,16 , the ability to disrupt the hydration shell and the water-mediated hydrogen bonds of collagen molecules, 17 and the dehydration process 10,[18][19][20] . In addition to penetration depth enhancement for tissue imaging [21][22][23] , OCAs also enable optical blood clearing 24 and monitoring of molecular diffusion [25][26][27][28][29][30] using OCT systems. Whereas OCA approaches use the scattering properties of tissue samples for the enhancement of the penetration depth, it has been recently demonstrated that controlling the illumination light in optical imaging can offer a high possibility of overcoming multiple scattering without affecting the sample.…”

One specific velocity color mapping using optical coherence tomography

“…Since it is difficult to register the Doppler shift of the carrier itself when applying ultrafast scanning techniques, [3][4][5][6][7][8][9][10][11][12][13][14] f D ¼ AE2V cosðαÞ∕λ 0 , we use the modified double pass rapid scanning optical delay (RSOD) 18,19 at lower scanning frequencies. RSOD allows the decoupling phase and group delay, as well as a shift of f c to the values of 20 to 30 kHz.…”