Assessment of Chronic Wounds Using In Vivo Diffuse Near Infrared Spectroscopy

Chronic wounds are an increasing challenge as the population ages and the prevalence of obesity and diabetes increase in the U.S. and throughout the world. As the number and cost of treatments for chronic wounds increases, the importance of assessing the effectiveness of new therapies becomes critical. Current clinical methods for wound assessment rely on qualitative assessment of wound surface appearance and measurements of wound surface dimensions, but do not take the health of underlying tissue into account. The goal of this research is to develop a non-invasive method of assessing and predicting chronic wound healing using in vivo frequency-domain diffuse near infrared spectroscopy (DNIRS). The main hypothesis behind this research is that changes in blood vessel density and oxygen delivery beneath the surface of a wound can be measured using DNIRS. Furthermore, these changes could be used to quantitatively assess the healing status of a chronic wound and predict faster and more accurately than current clinical methods whether a wound treatment is working.;The results of a study of twenty-eight human diabetic foot ulcers shows that changes in oxy- and total hemoglobin concentration measured with DNIRS can be used to differentiate healing from non-healing wounds, and the capability of DNIRS wound monitoring to predict healing in diabetic foot ulcers is examined. Additionally, data obtained from a study of impaired wound healing in obese rats demonstrate that DNIRS can be used to assess wound healing in an animal model, and a model for expected changes in DNIRS measurements of oxy- and deoxy-hemoglobin concentration during wound healing is proposed. Wound size data obtained from this animal study show that obese rats may provide a better model of impaired healing than the chemically-induced diabetic rats which are often used by researchers when assessing novel wound therapies.