Non-invasive evaluation of therapeutic response in keloid scar using diffuse reflectance spectroscopy

Abstract

Abstract:The pathogenesis and ideal treatment of keloid are still largely unknown, and it is essential to develop an objective assessment of keloid severity to evaluate the therapeutic response. We previously reported that our diffuse reflectance spectroscopy (DRS) system could assist clinicians in understanding the functional and structural condition of keloid scars. The purpose of this study was to understand clinical applicability of our DRS system on evaluating the scar severity and therapeutic response of keloid. We analyzed 228 spectral data from 71 subjects with keloid scars. The scars were classified into mild (0-3), moderate (4-7) and severe (8-11) according to the Vancouver scar scale. We found that as the severity of the scar increased, collagen concentration and water content increased, and the reduced scattering coefficient at 800 nm and oxygen saturation (SaO 2 ) decreased. Using the DRS system, we found that collagen bundles aligned in a specific direction in keloid scars, but not in normal scars. Water content and SaO 2 may be utilized as reliable parameters for evaluating the therapeutic response of keloid. In conclusion, the results obtained here suggest that the DRS has potential as an objective technique with which to evaluate keloid scar severity. In addition, it may be useful as a tool with which to track longitudinal response of scars in response to various therapeutic interventions.

Development of Measurement Instrument for Optical Properties of Human Skin in Vivo

“…Our measured results (e.g., " = 9.8 mm !1 at $ = 650 nm) are within the range of previous studies (e.g., " = 7.3-11.1 mm !1 at $ = 650 nm) [11,12]. Dispersions of the measured extinction coefficient at all wavelengths are much bigger than simulated percentage error of the instrument; for example, the dispersion before soaking in water at $ = 650 nm is 2.2%.…”

“…Thus far, the optical properties of skin have mainly been investigated for medical applications, with significant research reflecting this focus [9][10][11][12][13][14]. The methods used for measuring optical properties include the integrating sphere technique [10], diffuse optical spectroscopic imaging (DOSI) [11,12], and the reflection spatial profile measurement (RSPM) [14] proposed by the current authors.…”

“…The methods used for measuring optical properties include the integrating sphere technique [10], diffuse optical spectroscopic imaging (DOSI) [11,12], and the reflection spatial profile measurement (RSPM) [14] proposed by the current authors. Integrating sphere techniques are widely used to measure the optical properties of both skin and various scattering and absorbing media.…”

Light distribution modulated diffuse reflectance spectroscopy

“…Utilizing diffuse reflectance spectroscopy (DRS) to noninvasively estimate the absorption and scattering properties and physiological status of biological tissues has been successfully demonstrated by many groups [1][2][3][4]. In general, DRS systems can be categorized by the type of light source employed.…”

“…In general, DRS systems can be categorized by the type of light source employed. For example, DRS systems employing pulse lasers [2,5], intensity modulated lasers [1,6], and CW light sources [4,7] are usually categorized as time-domain, frequency-domain, and steady-state techniques, respectively. DRS systems equipping with different types of light source have their unique advantages and disadvantages.…”