The use of multiphoton imaging has become a standard technique to visualize the dermis fibers as it requires no specific staining. The density and organization of collagen and elastin are common markers of skin intrinsic aging and photoaging; thus, there is a need of grading this skin aging with quantitative indicators able to provide a robust evaluation of the dermis fibers’ state. We propose a systematic analysis of multiphoton images of skin biopsies taken on the buttock and the forearm of patients of different ages. The intensity histograms of images were analyzed through their moments, a wavelet decomposition was done, and the wavelet coefficients distribution was fitted by a generalized Gaussian distribution. Different parameters relative to the collagen or elastin densities, organizations, and structures were calculated and exhibit phenomena specific to intrinsic or extrinsic aging. Those indicators could become a standard method to analyze the degree of skin aging (intrinsic or extrinsic) through multiphoton imaging.
Diffuse reflectance spectroscopy characterizes composition and structure of tissues by determining their scattering and absorption properties. We have developed in our laboratory a low-cost spatially resolved diffuse reflectance spectroscopy instrument. We present in this study some results showing how to adapt this technology on multi-layered tissues. First of all, a method enabling determination of scattering and absorption properties of multi-layered phantoms is described; the adaptation of the initial methodology to focus on deep layers is especially detailed. Then some preliminary results obtained on a panel of volunteer’s redness faces are presented.