Quantitation of epidermal and mucosal tissue injury using contrast agents and imaging techniques

Background/purpose: Epidermal injury is common but the accuracy of visual methods is significantly impacted by the inherent skin pigmentation. We examined imaging and fluorescence techniques to quantify tissue injury as a function of skin color.
Methods: Epidermal and mucosal scratches were created in 20 light- ( L ^* 68.2±2.3) and 20 dark-skinned ( L ^* 46.4±5.2) females. Injured and uninjured sites were treated with toluidine blue (TB), fluorescein (FL) and a TB/FL mixture and photographed under conditions of white and fluorescent light. Area and intensity parameters were determined.
Results: Injured sites with TB and TB/FL had higher areas than the control for both light and dark subjects ( anova , P <0.05). The intensity of the injured TB site was higher than the control for light skin only. The areas of injured sites with FL and TB/FL were higher than the control for both groups as were the intensities of the injured sites with FL. The findings were similar for the lip skin.
Conclusions: Application of TB and FL contrasts under white and fluorescent light can be used to quantify tissue injuries for L ^* values >35 and is a promising approach for the quantitation across a range of skin pigmentation.