Objective assessment of clinical debridement and healing status of diabetic foot ulcers using a smartphone-based NIRS device

A smartphone-based near-infrared spectroscopy (NIRS) device (SPOT-smartphone-based oxygenation tool) was developed for remote patient monitoring of diabetic foot ulcers (DFUs). To date, SPOT has been validated through phantom studies and in-vivo studies against a commercial device. The current study focuses on developing an objective assessment of clinical debridement and healing status of diabetic foot ulcers using SPOT. Diffuse reflectance (690, 810, 830 nm) was captured and utilized to calculate tissue oxygenation maps by applying a modified Beer-Lamberts law. Fifteen DFU subjects were recruited and imaged using the SPOT device. In study 1, the effect of debridement on 37 cases were determined by imaging with SPOT before and after debridement. Spatial comparisons between the debrided (wound) and non-debrided regions on the tissue oxygenation maps indicated distinct differences upon debridement. Statistical analysis is ongoing to determine the extent of change in those parameters due to debridement. In study 2, the same 37 cases were evaluated, but only post-debridement to distinguish healing (H) and non-healing (NH) DFUs. Total hemoglobin (HbT) and oxygen saturation (StO₂) maps were utilized to create wound-to-surrounding contrasts for each quadrant. A threshold criterion using both parameters in conjunction classified the wound status. Ongoing work involves implementing statistical models, such as a generalized linear mixed effects model (GLMM), to predict DFU outcomes for a specific patient profile. This device allows for image-guided debridement and assessment of healing status.