Non-contact optical imaging of healing and non-healing diabetic foot ulcers

Abstract

Diabetic foot ulcer is the most devastating complication of diabetes that is still un-recognized. The treatment costs of these ulcers are very high to eventually save the leg/foot from amputation. To date, clinicians employ visual inspection of the wound site during its standard 4-week of healing process via monitoring of surface granulation. There is a need to develop on-site, low-cost imaging tools that can monitor the wound healing process periodically during the standard 4-week treatment process. A novel ultra-portable near-infrared optical scanner (NIROS) has been developed at the Optical Imaging Laboratory that can perform non-contact 2D area imaging of the wound site. Non-contact optical imaging studies were carried on diabetic subjects with foot ulcers (at Somesh Diabetic Foot Clinic, India) that were of healing and non-healing nature. A 710 nm LED source and a compact NIR sensitive camera were employed during non-contact imaging of the diabetic foot in order to obtain the near-infrared absorption images. From these preliminary studies it was observed that the non-healing wounds had a greater absorption contrast with respect to the normal site, unlike in the healing wounds. Demonstrating the ability of NIROS to differentiate healing vs. non-healing wounds in diabetic subjects can potentially impact early intervention in the treatment of diabetic foot ulcers.

Assessing the Healing of Venous Leg Ulcers Using a Noncontact Near-Infrared Optical Imaging Approach

“…Several research groups have implemented NIR optical imaging technology on wound imaging (chronic wounds and DFUs) with animal studies as well as pilot human subject studies. 5,[7][8][9][10][11][12][13][14][15][16][17] A summary of all the studies conducted with implementation of NIRS is listed in Table 1. Papazoglou's group and Weingarten's group at Drexel University conducted animal studies and a pilot human study to show that NIRS is capable of predicting wound healing in DFUs. [8][9][10][11][12][13][14] Moza et al developed a multiwavelength imager (no contact at the source end, but contact at the detector end) with real-time imaging display and demonstrated that NIRS is capable of imaging perfusion from studies on normal hands.…”

“…Recently, a near-infrared optical scanner (NIROS) has been developed at the Optical Imaging Laboratory, which is capable of noncontact whole wound imaging in real time. 16,17 Preliminary case studies demonstrated its ability to differentiate a healing from nonhealing wound based on differences in the optical contrast in lower extremity ulcers (DFUs and VLUs). [16][17][18] However, these preliminary studies were based on qualitative assessment of healing or nonhealing without assessing the effect of varying imaging conditions and image analysis in a clinic setting.…”

“…16,17 Preliminary case studies demonstrated its ability to differentiate a healing from nonhealing wound based on differences in the optical contrast in lower extremity ulcers (DFUs and VLUs). [16][17][18] However, these preliminary studies were based on qualitative assessment of healing or nonhealing without assessing the effect of varying imaging conditions and image analysis in a clinic setting. The current research focuses on applying NIROS to image VLUs and determine its ability to assess the healing or nonhealing nature consistently, under varying imaging and analysis conditions.…”

Diffuse Reflectance Imaging Differentiates Healing from Non- Healing Wounds in Diabetic Foot Ulcers

“…The technology uses near-infrared (NIR) light between 650-1000 nm to image deep tissues in order to map the spatial and temporal distribution of the optical properties (which translate to the oxy-and deoxy-hemoglobin changes) during repeated visits of the treatment process. Researchers have implemented NIRS towards wound healing studies in animals and pilot human subject studies as well [12,13,[22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Papazoglou and her group demonstrated that near-infrared spectroscopy (NIRS) can predict wound healing in human diabetic foot ulcers [12,13,24,25,[29][30][31][32].…”

“…The optical scanner has been recently used to demonstrate real-time dynamic imaging of the changes in blood flow in the dorsal of the hand during venous occlusion [26,27]. A pilot study demonstrated that NIROS could differentiate healing and non-healing lower extremity ulcer [34,35]. Herein, imaging studies were performed on 10 diabetic foot ulcers (healing and non-healing) in order to determine its ability to assess healing or non-healing consistently, under various imaging and analysis conditions.…”