Noncontact imaging of burn depth and extent in a porcine model using spatial frequency domain imaging

Abstract

Abstract. The standard of care for clinical assessment of burn severity and extent lacks a quantitative measurement. In this work, spatial frequency domain imaging (SFDI) was used to measure 48 thermal burns of graded severity (superficial partial, deep partial, and full thickness) in a porcine model. Functional (total hemoglobin and tissue oxygen saturation) and structural parameters (tissue scattering) derived from the SFDI measurements were monitored over 72 h for each burn type and compared to gold standard histological measurements of burn depth. Tissue oxygen saturation (stO 2 ) and total hemoglobin (ctHbT) differentiated superficial partial thickness burns from more severe burn types after 2 and 72 h, respectively (p < 0.01), but were unable to differentiate deep partial from full thickness wounds in the first 72 h. Tissue scattering parameters separated superficial burns from all burn types immediately after injury (p < 0.01), and separated all three burn types from each other after 24 h (p < 0.01). Tissue scattering parameters also showed a strong negative correlation to histological burn depth as measured by vimentin immunostain (r 2 > 0.89). These results show promise for the use of SFDIderived tissue scattering as a correlation to burn depth and the potential to assess burn depth via a combination of SFDI functional and structural parameters. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Quantitative long‐term measurements of burns in a rat model using Spatial Frequency Domain Imaging (SFDI) and Laser Speckle Imaging (LSI)

“…a). Previous research in similar rat burn experiments as well as pig burn experiments [ have shown a similar decrease in the μ s ’ values in the acute stages of burn wound progression. Additionally, they have shown that this decrease is proportional to the severity of the burn.…”

Thermal injury of skin and subcutaneous tissues: A review of experimental approaches and numerical models

“…It works under the principle that spatially modulated near-infrared light patterns of various spatial frequencies are projected over a large (over 100 cm 2 ) area of a sample and the reflected diffusive lights are captured with a camera, then demodulated to extract information of change in optical properties [100]. Capable of investigating tissue structure about 1–5 mm below the skin surface, SFDI is able to measure spatially resolved concentrations of clinically relevant chromophores including oxy-hemoglobin, de-oxy hemoglobin, lipid, water, and tissue oxygen saturation as well as the quantitative wide-field reduced scattering coefficients at each wavelength [101].…”

“…In particular, the differences in water concentration and optical scattering manifest themselves at as early as 10 minutes post-burn, while the difference in oxygenation does not occur until 50 minutes post-burn. Mazhar et al [100] performed an in vivo burn study on pigs and showed that optical scattering parameters differentiated superficial burns from all burn types immediately after injury, and separated all 3 degrees of burns 24 hours post-burn. On the other hand, tissue oxygenation is less sensitive to burn degree and cannot differentiate deep partial from full thickness wounds in 72 hours post-burn.…”

“…Thus multiple researchers chose to heat up a piece of metal and then place it on the animal to create desire burns. The metals are usually aluminum [48] [115] [116], brass [93] [100] [101] [117], stainless steel [118] or iron [92]. The burning devices are usually heated up to desired temperatures via immersion in boiling water.…”

Angle correction for small animal tumor imaging with spatial frequency domain imaging (SFDI)

“…When optical properties at multiple wavelengths are measured, tissue chromophore concentrations can be extracted to help identify disease states, therapy response, and tissue metabolic function. SFDI is being explored for a number of preclinical and clinical applications, including skin flap viability, burn wound healing, and subsurface tomography [3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”