NONINVASIVE MEDICAL DIAGNOSTICS THROUGH MULTISPECTRAL SKIN REFLECTANCE ANALYSIS: JAUNDICE DETECTION AND ERYTHEMA ASSESSMENT
Abstract
The objective of this research was to develop an optical method of providing medically useful information through measurement and analysis of the multispectral reflectance characteristics of the living skin. To establish a physical basis for the method, the optical behavior of the skin is examined and a physical model is developed; this absorbing-scattering model is used to relate the skin reflectance to specific physiologic conditions. The focus in this study is on demonstration of the utility of the skin reflectance diagnostic method in two particular problem areas: neonatal jaundice detection and ultraviolet erythema assessment. In the case of jaundice, the physical model is used to determine a relationship between skin reflectance and serum bilirubin concentration while erythematous skin reflectance is translated to an absolute vital measure related to vascular capacity. An experimental investigation is performed to demonstrate the suitability of the optical method in the jaundice and erythema applications. Representative jaundiced and erythematous skin spectra are obtained using a system specifically designed for rapid (3.6 seconds/scan) and convenient measurement of skin reflectance in vivo. This system measures the absolute reflectance of diffuse targets from 400 to 800 nm with moderate spectral resolution (10 nm) and is portable, self-contained and suitable for use in the clinical environment. Concurrent skin reflectance spectra and serum bilirubin concentrations were obtained on 58 white and 45 black full-term infants; measurements were performed on consecutive days for a number of infants such that a total of 221 observations were made. The sample population was divided into two groups according to race to reduce variations in pigmentation differences. Based upon an analysis accounting for the effects of hemoglobin and melanin, an optical parameter was derived to isolate the skin absorption due to bilirubin; this parameter is a function of the skin reflectance at three wavelengths (460,510 and 420 nm) and is linearly related to the serum bilirubin level. Serum bilirubins predicted from the optical parameter and the actual serum bilirubin concentration showed a correlation coefficient, R, of 0.78 for the white group and 0.86 for the black group; the standard error of estimate for the white and black groups are 1.6 and 1.5 mg/100 m1, respectively. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UMI
Degree
Ph.D.
Subject Area
Biomedical research
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