Monitoring Blood Glucose Changes in Cutaneous Tissue by Temperature-modulated Localized Reflectance Measurements

Abstract

Background: Most proposed noninvasive methods for glucose measurements do not consider the physiologic response of the body to changes in glucose concentration. Rather than consider the body as an inert matrix for the purpose of glucose measurement, we exploited the possibility that noninvasive measurements of glucose can be approached by investigating their effects on the skin's thermo-optical response. Methods: Glucose concentrations in humans were correlated with temperature-modulated localized reflectance signals at wavelengths between 590 and 935 nm, which do not correspond to any near-infrared glucose absorption wavelengths. Optical signal was collected while skin temperature was modulated between 22 and 38°C over 2 h to generate a periodic set of cutaneous vasoconstricting and vasodilating events, as well as a periodic change in skin light scattering. The method was tested in a series of modified meal tolerance tests involving carbohydrate-rich meals and no-meal or highprotein/no-carbohydrate meals. Results: The optical data correlated with glucose values. Changes in glucose concentrations resulting from a carbohydrate-rich meal were predicted with a model based on a carbohydrate-meal calibration run. For diabetic individuals, glucose concentrations were predicted with a standard error of prediction <1.5 mmol/L and a prediction correlation coefficient 0.73 in 80% of the cases. There were run-to-run differences in predicted glucose concentrations. Non-carbohydrate meals showed a high degree of scatter when predicted by a carbohydrate meal calibration model. Conclusions: Blood glucose concentrations alter thermally modulated optical signals, presumably through physiologic and physical effects. Temperature changes

The dynamics of invasive and noninvasive blood glucose monitoring methods: Recent trends

“…Недостатком явля-ется высокая стоимость, чувствительность к движениям тела и большая зависимость от изменения температуры тканей, что приводит к возникновению большого коли-чества артефактов при регистрации сигнала [32]. Кроме того, при сравнении с другими оптическими методиками метод не показал значимых преимуществ, при доста-точно высокой стоимости [33,34].…”

Infrared temperature measurements in micro-channels and micro-fluid systems

“…The temperature dependence has been known in NIR spectrometry in biomedical, agricultural, and polymer sciences, but it has usually been regarded as a disturbance. While some experimenters have made use of it to measure the temperature of various samples that contain water (Kakuta et al [42]; Lin and Brown [44]; Hollis et al [47]; Otal et al [48]; Thomson et al [49]), others have tried to cancel out the temperature effect in noninvasive measurements of glucose concentration (Arimoto et al [50]; Jensen et al [51]; Ye et al [52]; Cui et al [53]). …”

Temperature imaging of sub-millimeter-thick water using a near-infrared camera

“…The temperature dependence has been known in NIR spectrometry in biomedical, agricultural, and polymer sciences, but it has usually been regarded as a disturbance. While some experimenters have made use of it to measure the temperature of various samples that contain water [23,25,[28][29][30], others have tried to cancel out the temperature effect in noninvasive measurements of glucose concentration in vivo [31][32][33][34].…”