Wound size reduction has been the standard benchmark for determination of efficacy for diabetic u... more Wound size reduction has been the standard benchmark for determination of efficacy for diabetic ulcer treatments but due to interclinician error and difficulty measuring irregular wound shapes, this method is unreliable with a positive predictive value of less than 60%. Diffuse near-infrared spectroscopy (DNIRS) uses 70-MHz modulated light in the diagnostic window (650-900 nm) noninvasively to quantify levels of oxyand deoxy-hemoglobin in the wound bed, which when measured over time, can show a trend toward or away from healing based on the changes in oxy-hemoglobin concentration from week to week. In this study, DNIRS was used to monitor 24 human diabetic foot ulcers longitudinally over the course of 20 weekly or biweekly measurement sessions. In just 4 weeks, the DNIRS system has an 82% positive predictive value (sensitivity of 0.9 and specificity of 0.86; p < 0.002). These data indicate that it could be possible to predict healing in 4 weeks using DNIRS, which can provide objective guidance toward the continuation of costly treatments. Discontinuing ineffective treatments after 4 weeks could have potentially saved over $12,600 per patient, based on the treatment regimen of patients in this study.
ABSTRACT Forty-six human diabetic foot ulcers were measured with Diffuse Near-Infrared Spectrosco... more ABSTRACT Forty-six human diabetic foot ulcers were measured with Diffuse Near-Infrared Spectroscopy. The weekly change in oxy-hemoglobin concentration could distinguish healing and non-healing ulcers with a sensitivity of 0.9 and specificity of 0.86 (p&lt;0.002)
ABSTRACT Our goal was to quantitatively assess capillary reperfusion as it relates to arterial di... more ABSTRACT Our goal was to quantitatively assess capillary reperfusion as it relates to arterial disease and tobacco use. This method could prove to be an alternate, quantitative diagnostic technique to a routine segmental arterial study.
Diffuse photon density wave (DPDW) methodology is widely used in a number of biomedical applicati... more Diffuse photon density wave (DPDW) methodology is widely used in a number of biomedical applications. Here, we present results of Monte Carlo simulations that employ an effective numerical procedure based upon a description of radiative transfer in terms of the Bethe–Salpeter equation. A multifrequency noncontact DPDW system was used to measure aqueous solutions of intralipid at a wide range of source–detector separation distances, at which the diffusion approximation of the radiative transfer equation is generally considered to be invalid. We find that the signal–noise ratio is larger for the considered algorithm in comparison with the conventional Monte Carlo approach. Experimental data are compared to the Monte Carlo simulations using several values of scattering anisotropy and to the diffusion approximation. Both the Monte Carlo simulations and diffusion approximation were in very good agreement with the experimental data for a wide range of source–detector separations. In addit...
Advanced Biomedical and Clinical Diagnostic Systems XII, 2014
ABSTRACT The ability to determine the depth and degree of cutaneous and subcutaneous tissue damag... more ABSTRACT The ability to determine the depth and degree of cutaneous and subcutaneous tissue damage is critical for medical applications such as burns and pressure ulcers. The Diffuse Photon Density Wave (DPDW) methodology at near infrared wavelengths can be used to non-invasively measure the optical absorption and reduced scattering coefficients of tissue at depths of several millimeters. A multi-frequency DPDW system with one light source and one detector was constructed so that light is focused onto the tissue surface using an optical fiber and lens mounted to a digitally-controlled actuator which changes the distance between light source and detector. A variable RF generator enables the modulation frequency to be selected between 50 to 400MHz. The ability to digitally control both source-detector separation distance and modulation frequency allows for virtually unlimited number of data points, enabling precise selection of the volume and depth of tissue that will be characterized. Suspensions of Intralipid and india ink with known absorption and reduced scattering coefficients were used as optical phantoms to assess device accuracy. Solid silicon phantoms were formulated for stability testing. Standard deviations for amplitude and phase shift readings were found to be 0.9% and 0.2 degrees respectively, over a one hour period. The ability of the system to quantify tissue damage in vivo at multiple depths was tested in a porcine burn model.
Wound size reduction has been the standard benchmark for determination of efficacy for diabetic u... more Wound size reduction has been the standard benchmark for determination of efficacy for diabetic ulcer treatments but due to interclinician error and difficulty measuring irregular wound shapes, this method is unreliable with a positive predictive value of less than 60%. Diffuse near-infrared spectroscopy (DNIRS) uses 70-MHz modulated light in the diagnostic window (650-900 nm) noninvasively to quantify levels of oxyand deoxy-hemoglobin in the wound bed, which when measured over time, can show a trend toward or away from healing based on the changes in oxy-hemoglobin concentration from week to week. In this study, DNIRS was used to monitor 24 human diabetic foot ulcers longitudinally over the course of 20 weekly or biweekly measurement sessions. In just 4 weeks, the DNIRS system has an 82% positive predictive value (sensitivity of 0.9 and specificity of 0.86; p < 0.002). These data indicate that it could be possible to predict healing in 4 weeks using DNIRS, which can provide objective guidance toward the continuation of costly treatments. Discontinuing ineffective treatments after 4 weeks could have potentially saved over $12,600 per patient, based on the treatment regimen of patients in this study.
Wound size reduction has been the standard benchmark for determination of efficacy for diabetic u... more Wound size reduction has been the standard benchmark for determination of efficacy for diabetic ulcer treatments but due to interclinician error and difficulty measuring irregular wound shapes, this method is unreliable with a positive predictive value of less than 60%. Diffuse near-infrared spectroscopy (DNIRS) uses 70-MHz modulated light in the diagnostic window (650-900 nm) noninvasively to quantify levels of oxyand deoxy-hemoglobin in the wound bed, which when measured over time, can show a trend toward or away from healing based on the changes in oxy-hemoglobin concentration from week to week. In this study, DNIRS was used to monitor 24 human diabetic foot ulcers longitudinally over the course of 20 weekly or biweekly measurement sessions. In just 4 weeks, the DNIRS system has an 82% positive predictive value (sensitivity of 0.9 and specificity of 0.86; p < 0.002). These data indicate that it could be possible to predict healing in 4 weeks using DNIRS, which can provide objective guidance toward the continuation of costly treatments. Discontinuing ineffective treatments after 4 weeks could have potentially saved over $12,600 per patient, based on the treatment regimen of patients in this study.
ABSTRACT Forty-six human diabetic foot ulcers were measured with Diffuse Near-Infrared Spectrosco... more ABSTRACT Forty-six human diabetic foot ulcers were measured with Diffuse Near-Infrared Spectroscopy. The weekly change in oxy-hemoglobin concentration could distinguish healing and non-healing ulcers with a sensitivity of 0.9 and specificity of 0.86 (p&lt;0.002)
ABSTRACT Our goal was to quantitatively assess capillary reperfusion as it relates to arterial di... more ABSTRACT Our goal was to quantitatively assess capillary reperfusion as it relates to arterial disease and tobacco use. This method could prove to be an alternate, quantitative diagnostic technique to a routine segmental arterial study.
Diffuse photon density wave (DPDW) methodology is widely used in a number of biomedical applicati... more Diffuse photon density wave (DPDW) methodology is widely used in a number of biomedical applications. Here, we present results of Monte Carlo simulations that employ an effective numerical procedure based upon a description of radiative transfer in terms of the Bethe–Salpeter equation. A multifrequency noncontact DPDW system was used to measure aqueous solutions of intralipid at a wide range of source–detector separation distances, at which the diffusion approximation of the radiative transfer equation is generally considered to be invalid. We find that the signal–noise ratio is larger for the considered algorithm in comparison with the conventional Monte Carlo approach. Experimental data are compared to the Monte Carlo simulations using several values of scattering anisotropy and to the diffusion approximation. Both the Monte Carlo simulations and diffusion approximation were in very good agreement with the experimental data for a wide range of source–detector separations. In addit...
Advanced Biomedical and Clinical Diagnostic Systems XII, 2014
ABSTRACT The ability to determine the depth and degree of cutaneous and subcutaneous tissue damag... more ABSTRACT The ability to determine the depth and degree of cutaneous and subcutaneous tissue damage is critical for medical applications such as burns and pressure ulcers. The Diffuse Photon Density Wave (DPDW) methodology at near infrared wavelengths can be used to non-invasively measure the optical absorption and reduced scattering coefficients of tissue at depths of several millimeters. A multi-frequency DPDW system with one light source and one detector was constructed so that light is focused onto the tissue surface using an optical fiber and lens mounted to a digitally-controlled actuator which changes the distance between light source and detector. A variable RF generator enables the modulation frequency to be selected between 50 to 400MHz. The ability to digitally control both source-detector separation distance and modulation frequency allows for virtually unlimited number of data points, enabling precise selection of the volume and depth of tissue that will be characterized. Suspensions of Intralipid and india ink with known absorption and reduced scattering coefficients were used as optical phantoms to assess device accuracy. Solid silicon phantoms were formulated for stability testing. Standard deviations for amplitude and phase shift readings were found to be 0.9% and 0.2 degrees respectively, over a one hour period. The ability of the system to quantify tissue damage in vivo at multiple depths was tested in a porcine burn model.
Wound size reduction has been the standard benchmark for determination of efficacy for diabetic u... more Wound size reduction has been the standard benchmark for determination of efficacy for diabetic ulcer treatments but due to interclinician error and difficulty measuring irregular wound shapes, this method is unreliable with a positive predictive value of less than 60%. Diffuse near-infrared spectroscopy (DNIRS) uses 70-MHz modulated light in the diagnostic window (650-900 nm) noninvasively to quantify levels of oxyand deoxy-hemoglobin in the wound bed, which when measured over time, can show a trend toward or away from healing based on the changes in oxy-hemoglobin concentration from week to week. In this study, DNIRS was used to monitor 24 human diabetic foot ulcers longitudinally over the course of 20 weekly or biweekly measurement sessions. In just 4 weeks, the DNIRS system has an 82% positive predictive value (sensitivity of 0.9 and specificity of 0.86; p < 0.002). These data indicate that it could be possible to predict healing in 4 weeks using DNIRS, which can provide objective guidance toward the continuation of costly treatments. Discontinuing ineffective treatments after 4 weeks could have potentially saved over $12,600 per patient, based on the treatment regimen of patients in this study.
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