Hyperspectral Imaging for Burn Depth Assessment in an Animal Model

Abstract

Background:Differentiating between superficial and deep-dermal (DD) burns remains challenging. Superficial-dermal burns heal with conservative treatment; DD burns often require excision and skin grafting. Decision of surgical treatment is often delayed until burn depth is definitively identified. This study’s aim is to assess the ability of hyperspectral imaging (HSI) to differentiate burn depth.Methods:Thermal injury of graded severity was generated on the dorsum of hairless mice with a heated brass rod. Perfusion and oxygenation parameters of injured skin were measured with HSI, a noninvasive method of diffuse reflectance spectroscopy, at 2 minutes, 1, 24, 48 and 72 hours after wounding. Burn depth was measured histologically in 12 mice from each burn group (n = 72) at 72 hours.Results:Three levels of burn depth were verified histologically: intermediate-dermal (ID), DD, and full-thickness. At 24 hours post injury, total hemoglobin (tHb) increased by 67% and 16% in ID and DD burns, respectively. In contrast, tHb decreased to 36% of its original levels in full-thickness burns. Differences in deoxygenated and tHb among all groups were significant (P < 0.001) at 24 hours post injury.Conclusions:HSI was able to differentiate among 3 discrete levels of burn injury. This is likely because of its correlation with skin perfusion: superficial burn injury causes an inflammatory response and increased perfusion to the burn site, whereas deeper burns destroy the dermal microvasculature and a decrease in perfusion follows. This study supports further investigation of HSI in early burn depth assessment.

Association between cumulative radiation dose, adverse skin reactions, and changes in surface hemoglobin among women undergoing breast conserving therapy

“…We have utilized a commercially produced HSI device, which provides near real-time analysis of oxygenated and deoxygenated hemoglobin (OxyHb and DeoxyHb, respectively) content in skin. In previous animal studies, we successfully demonstrated that this technology reliably detects and assesses skin changes after exposure to both ionizing and thermal radiation [6] , [7] , [8] . Our translational studies on the acute phase suggest that cutaneous changes in oxygenation may be dose related and that this may be a potential surrogate marker for radiation exposure [9] .…”

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

“…Previous experiments using a similar rat burn model have shown acute increases in deoxygenated hemoglobin for deep burns [29]. Studies in mice [34] and pig burn models [35] have also shown increases in deoxygenated hemoglobin over a 72 hour period. Here, we have characterized the changes in deoxygenated hemoglobin at time points that are well past the early inflammation stages of wound healing and into the later proliferation and maturation stages.…”

Evaluating clinical observation versus Spatial Frequency Domain Imaging (SFDI), Laser Speckle Imaging (LSI) and thermal imaging for the assessment of burn depth

“…These techniques utilize images taken at multiple wavelengths of light to measure the reflectance from burn tissue [11,12]. These reflectance measurements can be converted into concentrations of chromophores such oxygenated and deoxygenated hemoglobin, but require assumptions about the reduced scattering coefficient [13,14]. Differences in oxygenated and deoxygenated hemoglobin concentrations of burn wound regions and unburned skin indicate damage to the underlying vasculature which can be indicative of burn severity.…”