Quantitative characterization of vascular targeted photodynamic therapy efficiency for port-wine stains using image processing techniques

Vascular targeted photodynamic therapy (V-PDT) is a clinically approved therapeutic approach for treating vascular-related diseases, such as port-wine stains (PWS). For accurate treatment, various light doses are required for different lesions due to the irregularity of vascular size, shape, degree of disease, which commonly alters during different stages of V-PDT, making quantitative analysis of treatment efficiency is highly needed. Lesion images before and after V-PDT treatment of patients with PWS were used to construct a quantitative method to characterize the differences among lesions. Image analysis techniques were applied to calculate Euclidean distances and two-dimensional correlation coefficients for V-PDT efficiency evaluation. According to the image analysis, V-PDT with good treatment efficiency resulted in a larger Euclidean distance and a smaller correlation coefficient, in comparison with the case having lower V-PDT efficiency. The new method to quantify the Euclidean distances and correlation coefficients is developed, which is promising for the quantitative analysis of V-PDT efficiency for PWS.