Lower extremity wound imaging using a hand-held near-infrared optical scanner

Lower extremity wounds currently afflict over 6 million persons in the U.S.  Among the elderly, the prevalence of chronic limb ulceration approaches 15% and is increasing.  To date, clinicians employ visual inspection of the wound site during its healing process via monitoring of surface granulation.  In some cases, surface granulation may not be an implication of internal healing.  There is a need to develop a point-of-care, low-cost imaging tools that can objectively determine if a wound is healing or not.  Herein, a portable, low-cost, non-invasive, and non-contact based near-infrared optical scanner (NIROS) has been implemented to optically differentiate healing from non-healing wounds.  Non-contact, non-radiative real-time imaging was performed on diabetic subjects with lower extremity wounds (e.g. diabetic foot ulcers, venous leg ulcers). The near-infrared optical images acquired from the wound site were processed to obtain optical contrast ratio between the wound and its background under various conditions of experimental conditions.  Preliminary analysis from 20 wounds showed a sensitivity of 92% and a specificity of 97% in differentiating a wound as healing or non-healing.  A portable, easy to use point-of -care near-infrared optical scanner demonstrated its capability to classify a healing from non-healing wound.  Future work will involve systematic assessment of not only lower extremity wounds, but pressure ulcers to determine their healing.