Using noninvasive multispectral imaging to quantitatively assess tissue vasculature

Abstract

This research describes a noninvasive, noncontact method used to quantitatively analyze the functional characteristics of tissue. Multispectral images collected at several near-infrared wavelengths are input into a mathematical optical skin model that considers the contributions from different analytes in the epidermis and dermis skin layers. Through a reconstruction algorithm, we can quantify the percent of blood in a given area of tissue and the fraction of that blood that is oxygenated. Imaging normal tissue confirms previously reported values for the percent of blood in tissue and the percent of blood that is oxygenated in tissue and surrounding vasculature, for the normal state and when ischemia is induced. This methodology has been applied to assess vascular Kaposi's sarcoma lesions and the surrounding tissue before and during experimental therapies. The multispectral imaging technique has been combined with laser Doppler imaging to gain additional information. Results indicate that these techniques are able to provide quantitative and functional information about tissue changes during experimental drug therapy and investigate progression of disease before changes are visibly apparent, suggesting a potential for them to be used as complementary imaging techniques to clinical assessment.

Remote diffuse reflectance spectroscopy sensor for tissue engineering monitoring based on blind signal separation

“…In this study the first results on angiogenesis evaluation and assessment of bioengineered skin substitutes using a portable Diffuse Reflectance Spectroscopy (DRS) system [4] with a non-contact optical probe are shown. The analysis of the measured reflectances at different wavelengths is performed using two Blind Signal Separation (BSS) methods: Principal Component Analysis (PCA) and Independent Component Analysis (ICA).…”

Rapid and accurate estimation of blood saturation, melanin content, and epidermis thickness from spectral diffuse reflectance

“…This technique investigates tissue structure, chromophore concentration, and health by measuring the tissue's optical properties. Commercially available devices typically analyze experimental data using the modified Beer-Lambert's law to determine the relative concentrations of tissue chromophores such as melanin, blood, water, or hemoglobin in arbitrary units [6,[8][9][10][11][12][13]. However the tissue scattering coefficient cannot be retrieved [10,14].…”

Illumination Compensation and Normalization Using Low-Rank Decomposition of Multispectral Images in Dermatology

“…Vogel et al [13] present a radiometrically calibrated multispectral imaging system to assess tissue vasculature. The authors model both the distribution of the illumination across the image and the geometry of the subject.…”

“…This method has the most similar input data and hardware to our own, however, most of the influences of illumination are corrected through a calibrated and controlled acquisition environment. Unlike Vogel et al [13] we make no assumptions about either the distribution of light intensity or the geometry of the scene.…”