In vivo evaluation of burn severity in skin tissue of rats using hemoglobin parameters estimated by red-green-blue imaging.

Abstract

Significance: Burn injuries are a global public health problem and are estimated to cause more than 150,000 deaths annually. Even non-fatal burns result in prolonged hospitalization, disfigurement, and disability. The depth of the burn injury is crucial information for selecting adequate treatment for burns. The most common, convenient, and widely used method for assessing burn severity is visual examination, but the accuracy of this method is insufficient, at only 60% to 75%. Rapid and accurate assessment of burn severity is critical for optimal management and treatment of burn patients. Methods of burn severity assessment that are inexpensive, simple, rapid, non-contact, and non-invasive are thus needed.

Aim: We aim to propose an approach to visualize the spatial distribution of burn severity using hemoglobin parameters estimated from a snapshot red-green-blue (RGB) color image and to demonstrate the feasibility of this proposed approach for differentiating burn severity in a rat model of scald burn injury.

Approach: The approach to creating a spatial map of burn severity was based on canonical discriminant analysis (CDA) of total hemoglobin concentration, tissue oxygen saturation, and methemoglobin saturation as estimated from RGB color images. Burns of two different degrees of severity were created in rat dorsal skin by 10-s exposure to water maintained at 70°C and 78°C. RGB color images for the dorsal regions were acquired under anesthesia before burn injury and at 24, 48, and 72 h after injury.

Results: Most areas of images in the groups with skin exposed to 70°C, 78°C, and 37°C water were classified as 70°C burn, 78°C burn, and non-burned normal skin, respectively, over 48 to 72 h. In contrast, classification images of the skin group exposed to 70°C water for 24 h showed a mixture of non-burned normal skin and 70°C burned areas, suggesting that burn severity was heterogeneous.

Conclusions: The proposed approach combining RGB color imaging and CDA appears promising for differentiating 78°C burns from 70°C burns and non-burned normal skin and non-burned normal skin from 70°C and 78°C burns at 24 to 72 h after burn injury in a rat model of scald burn injury.