. 2020 Mar 19;9(5):245–263. doi: 10.1089/wound.2019.0967

Table 5.

Comparison of commonly used optical imaging modalities for wound monitoring

Imaging modalities	Principle and application	Advantages	Disadvantage
Digital camera imaging	Optical images processed by software.	Simple, universal applicability.	Lack of physiological information.
Digital camera imaging	Determine surface wound size, wound boundary; build 3D structure; assess the stages of chronic wounds.	Simple, universal applicability.	Lack of physiological information.
Hyperspectral imaging	Capture a series of images recording the intensity of diffusely reflected light from the wounded tissue and generate a three-dimensional data cube.	Simple, suitable for microvasculature abnormality of chronic wounds.	Limited imaging depth
Hyperspectral imaging	Quantify factors including oxyhemoglobin, deoxyhemoglobin, and blood oxygen saturation; measure burn wound depth; evaluate healing potential of diabetic foot ulcers.		Limited imaging depth
Thermal imaging	Measure infrared radiation emitted from the wound tissue using an infrared camera.	Simple, portable, real-time imaging.	Limited accuracy, specificity, and sensitivity.
Thermal imaging	Quantify the extent and stage of wound healing process and measure the depth of burn wounds.	Simple, portable, real-time imaging.	Limited accuracy, specificity, and sensitivity.
Optical coherence tomography	Generate cross-sectional images of internal microstructure of the tissue based on low-coherence interferometry.	High resolution, suitable for noninvasively monitoring wound healing processes.	Limited imaging depth.
Optical coherence tomography	Monitor wound dimension, epidermal migration, dermal-epidermal junction formation, vasodilation, vasoconstriction, and epithelization during wound healing process.		Limited imaging depth.
Laser Doppler imaging	Measure wavelength variations of reflected and scattered electromagnetic radiation after encountering moving red blood cells and static surrounding tissue.	Real-time imaging, suitable for burn wound monitoring.	Low accuracy, not feasible for diabetic patient with lower limb perfusion.
Laser Doppler imaging	Acquire quantitative information of blood flow, perfusion, and microvasculature in real time; predict burn wound treatment outcome and healing time.	Real-time imaging, suitable for burn wound monitoring.
Spatial frequency domain imaging	Reveal optical properties of wounded tissue through separating and quantifying absorbed and scattered incoherent monochromatic light.	Noncontact, able to distinguish infection and noninfected wounds.	Limited scanning area, high time consuming.
Spatial frequency domain imaging	Measure oxygen saturation, blood volume, and water fraction; interpret vascularization and infection of the wounded tissue.		Limited scanning area, high time consuming.
Fluorescence imaging	Detect either autofluorescence of endogenous fluorophores or administered exogenous fluorescent dyes at the wound site.	High optical contrast, simple imaging process and condition.	Minimally invasive due to intravenous injection of ICG.
Fluorescence imaging	Monitor wound healing process through measuring oxidative phosphorylation and cellular metabolism activity to reveal vascularization and wound depth at the wound region.		Minimally invasive due to intravenous injection of ICG.
Near-infrared spectroscopy	Measure maximum light absorption wavelengths of different components, which are associated with blood oxygen saturation, hemoglobin content, and water content.	Noninvasive, high resolution.	Lack of specificity.
Near-infrared spectroscopy	Compute burn wound depth; quantify edema; monitor diabetic ulcers and burn wound healing process.	Noninvasive, high resolution.	Lack of specificity.

ICG, indocyanine green.