Abstract: 【Abstract】 Objective To assess the application value of reflectance confocal microscopy （RCM） in evaluating clinical efficacy of hemoporfin-mediated photodynamic therapy for purple-type port-wine stain. Methods From April 2018 to January 2020, a total of 39 patients with centrofacial purple-type port-wine stains were enrolled from Department of Dermatology, Wuhan No.1 Hospital, and received 3 sessions of hemoporfin-mediated photodynamic therapy. Before the first treatment, and 3 - 6 months after 3 sessions of hemoporfin-mediated photodynamic therapy, skin lesions were photographed, and RCM was conducted to measure the diameter and density of blood vessels at a depth of 100 μm in the lesions. Clinical efficacy was evaluated based on the clinical photos, and the average diameter of blood vessels and density of blood vessels per square millimeter of lesion area were calculated. Measurement data were compared among different groups by using one-way analysis of variance, multiple comparisons were performed using least significant difference test, and comparisons of parameters before and after treatment were conducted by using paired t test. Results After 3 sessions of hemoporfin-mediated photodynamic therapy, 1 （2.56%） patient was nearly completely cured, 16 （41.03%） received marked improvement, 20 （51.28%） received improvement, and 2 （5.13%） showed no response to the treatment. In the patients receiving marked improvement or improvement, the average diameter and density of blood vessels significantly decreased after treatment compared with those before treatment （all P < 0.05）, while no significant difference was observed before and after treatment in the patients with no response （both P > 0.05）. The average difference in the blood vessel diameter before and after treatment was significantly higher in the patients receiving marked improvement （48.56 ± 17.87 μm） than in those receiving improvement （31.15 ± 21.09 μm, P < 0.05） and those with no response （12.00 ± 2.83 μm, P < 0.05）. The average difference in the blood vessel density before and after treatment was 7.13 ± 3.44, 5.00 ± 2.22 and -0.50 ± 3.54 vessels/mm2,respectively, in the patients receiving marked improvement, improvement and those with no response, and pairwise comparisons between the 3 groups all showed significant differences （all P < 0.05）. Conclusion RCM can be used to assess the average diameter and density of blood vessels in the port-wine stain lesions before and after hemoporfin-mediated photodynamic therapy, and is helpful in quantitatively evaluating the therapeutic effect of hemoporfin-mediated photodynamic therapy.

Key words: Port-wine stain, Photochemotherapy, Microscopy, confocal, Treatment outcome, Hemoporfin