ИСТИНА

Edema is a swelling effect caused by accumulation of fluid in tissues under the skin. It may manifest itself due to pregnancy and medical conditions such as heart failure. The common method for edema characterizing is known as pitting, which is a procedure when pressure is applied to the swelling part of patient’s body and restoration of the “pit” is observed. This method provides general picture and is not capable of quantitative characterization of the process. It is evident that swelling may be described by the water content in the tissue and it can be done using spectroscopic technique. In our recent work [1], we have suggested a method for characterizing edema severity using optical microscopy, which was based on the assessment of the viable epidermis size. However, this method is complicated when there is a need to produce a serial medical device. The most reasonable way for non-invasive measurement of water content in tissues is reflectance spectrometry. Currently, some commercial devices based on the method of diffuse reflectance spectroscopy were proposed to characterise human skin chromophore contents [2]. We assembled a setup for diffusive reflectance spectroscopy measurements, prepared different phantoms of human skin, including liquid and soft matter phantoms with varying water and chromophores contents, and carried out measurements of diffusive reflectance spectra for them. As expected, reflectance spectra demonstrated correlation with chromophores contents. Since the reflectance spectra is mainly determined by two processes, namely scattering and absorption, it was necessary to develop the method for characterization of skin absorption using data of reflectance spectroscopy. The process of light propagation in the human skin was simulated using Monte-Carlo method on the cluster of GPU nodes [3] with the modified version of GPU-MCML program [4]. The results of simulations was utilized to develop statistical methods of diffusive reflectance spectra processing which allowed to estimate contribution of absorbance into observed spectra. These methods were applied for processing of data obtained using skin phantoms. After that, a series of experiments on humans were performed, which allowed to estimate reliability of the proposed method for clinical applications. The research was carried out using the equipment of the shared research facilities of HPC computing resources at Lomonosov Moscow State University. The work was supported by the Russian Science Foundation (grant №18-15-00422).