Determination of burn depth with noncontact ultrasonography

Early excision and grafting is the current treatment of choice for deep dermal and full-thickness burn wounds that will not heal spontaneously within 3 weeks. The time needed for the burn wound to heal is estimated with clinical assessment of the burn depth; this is often an inaccurate method. Therefore we have developed a new and unique noncontact ultrasonographic method to estimate burn depth. This study was designed to determine the practical utility and accuracy of noncontact ultrasonography for the assessment of burn depth. Seventy-eight burn sites and 42 normal skin sites (control sites) of 15 patients (age, 18-63 years) with burns of 2% to 35% total body surface area were evaluated. The burn sites were scanned with a prototype noncontact ultrasonographic system 1 and 3 days after the burn injuries. The probe was held 1 inch from the skin, and the time spent on each site was approximately 5 minutes. The ultrasonographic results were interpreted by an investigator who was blinded to the clinical findings. Clinical assessment of the burn wounds was made on the same days by 2 experienced physicians who were blinded to the results of the ultrasonography. The investigators were asked to categorize the burn wounds into those that would heal within 3 weeks and those that would not. With this method, we were able to visualize the epidermis, dermis, and dermal-fat interface in normal skin. The destruction of the dermal-fat interface was interpreted as a deep burn, which would not heal within 3 weeks. The overall accuracy of the noncontact ultrasonography in the prediction of which burn wounds would heal within 3 weeks was 96%. The results of this study show that noncontact ultrasonography will allow for the rapid evaluation of burn depth with high accuracy, without contacting the patient, and without causing pain or discomfort.