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Updated: May 2, 2026

Diffuse Reflectance Spectroscopy: Getting the Capillary Refill Test Under One's Thumb
Published on: December 2, 2017
Handheld Diffuse Reflectance Spectral Imaging (DRSi) for in-vivo characterization of skin
Sheldon F Bish1, Manu Sharma1, Youmin Wang1
1Department of Biomedical Engineering, The University of Texas at Austin, 107. W. Dean Keeton St. Austin TX 78712, USA.
Abstract:
Diffuse reflectance spectroscopy provides a noninvasive means to measure optical and physiological properties of tissues. To expand on these measurements, we have developed a handheld diffuse reflectance spectral imaging (DRSi) system capable of acquiring wide field hyperspectral images of tissue. The image acquisition time was approximately 50 seconds for a 50x50 pixel image. A transport model was used to fit each spectra for reduced scattering coefficient, hemoglobin concentration and melanin concentration resulting in optical property maps. The system was validated across biologically relevant levels of reduced scattering (5.14% error) and absorption (8.34% error) using tissue simulating phantoms. DRSi optical property maps of a pigmented skin lesion were acquired in vivo. These trends in optical properties were consistent with previous observations using point probe devices.

