Chronic wounds cause considerable morbidity and are an economic burden on healthcare systems. Techniques that allow effective diagnosis of chronic wounds aid better treatment plans leading to faster healing simultaneously time reducing treatment costs.

Visual observation and standard diagnostic imaging modalities (computed tomography (CT), single photon emission computed tomography (SPECT)/CT, magnetic resonance imaging (MRI), ultrasound imaging, terahertz (THz) spectroscopy) are used to evaluate chronic wounds. Pulse oximeters have been used in patients with venous leg ulcers and impending diabetic ulcers to determine arterial insufficiency. Subepidermal moisture (SEM) scanner is an up-and-coming tool to evaluate the risk of developing pressure ulcers. Wound swabs and biopsies and biochemical analysis of wound exudate are other assessment methods for chronic wounds.

Wound imaging gives information about the size and depth of wound, the blood flow, any inflammation and infection, but they cannot assess the changes in wound environment. The high equipment costs and long duration of imaging further deter their routine use in wound care.

Newer optical imaging modalities such as digital camera imaging, hyperspectral imaging (HSI), thermal imaging, optical coherence tomography (OCT), laser Doppler imaging (LDI), spatial frequency domain imaging (SFDI), fluorescence imaging, NIR imaging spectroscopy are more suitable for routine care of wound as they do not involve long imaging time and are less dependent on imaging environment. Multispectral imaging is an emerging technique used in wound care by helping to examine several wound assessment factors at one go. 

Several markers have also been identified to monitor the complex process of wound healing and detect various changes in the wound environment. These include bacterial load, microbial cytokine, DNA, matrix metalloproteinase (MMP), growth factors, immunohistochemical markers, inflammatory mediators, nitric oxide, pH, reactive oxygen species (ROS), temperature, tissue oxygenation, and transepidermal water loss from periwound skin. This review has discussed the role of standard imaging modalities, newer developments in the marker-based imaging probe for optical wound imaging and their ability to effectively detect any alteration in the wound environment. Optical wound imaging may have a critical role in wound diagnosis and routine care of wound in the newer future. 

Shuxin Li, et al. Adv Wound Care (New Rochelle). 2020 May 1;9(5):245-263