Clinical Application Of 20MHz And 50MHz High-frequency Ultrasound In Predicting The Efficacy Of Flat Port-wine Stains

Objective: To investigate the clinical value of 20 MHz and 50 MHz high frequency ultrasound in flat port-wine stains.Methods: According to the inclusion criteria,54 patients with flat port-wine stains on the face and neck who were admitted to the dermatology clinic of affiliated hospital of guilin medical university from June 2018 to December 2018 for pulsed dye laser treatment were selected,with a total of 60 lesions.Before treatment,20 MHz and 50 MHz high-frequency ultrasound was used to detect the thickness and density values of the dermis in the skin lesions and adjacent normal parts of the patients.SPSS25.0 software was used for statistics.The independent sample t test compared the thickness and density values of two high-frequency ultrasonic measurements with different frequencies.Patients after six pulsed dye laser therapy,with a global doctor evaluation method according to the change of the color,area divided the patients into the lesion site is invalid,effective group and group were markedly improved,The chi-square test was used to compare the gender of each group,and the non-parametric rank sum test was used to compare the age of each group,orderly classification using single factor analysis of variance and multiple Logistic regression analysis of many factors,the skin leather thickness,density,and compare the correlation of laser treatment effect.Results:(1)20MHz high-frequency ultrasound was used to measure the dermal thickness and density values of skin lesions and adjacent normal skin parts.The thickness of skin lesions was greater than that of normal skin parts,and the density of skin lesions was less than that of normal skin parts.The differences between the two were statistically significant(p<0.05).(2)The dermal thickness and density values of skin lesions and adjacent normal parts were measured by 50 MHz high-frequency ultrasound.The thickness of skin lesions was greater than that of normal parts,and the density of skin lesions was less than that of normal parts.The differences between the two were statistically significant(p<0.05).(3)When measuring the dermal thickness of normal skin,there was no significant difference between 20 MHz and 50 MHz high-frequency ultrasound(p>0.05).When measuring the thickness of dermis,20 MHz high-frequency ultrasound was greater than 50 MHz high-frequency ultrasound,and the difference between the two was statistically significant(p<0.05).(4)The dermal density value of normal skin was measured.The 20 MHz high-frequency ultrasonic measurement was greater than 50 MHz high-frequency ultrasonic measurement,and the difference between the two was statistically significant(p<0.05).When measuring dermal density value of skin lesions,20 MHz high-frequency ultrasound was greater than 50 MHz high-frequency ultrasound,and the difference between the two was statistically significant(p<0.05).(5)According to the curative effect,the patients were divided into 12 ineffective groups,40 effective groups and 8 markly effective groups,there was no statistical significance in gender and age of each group(p>0.05).(6)Univariate analysis of variance showed that the density values measured by 20 MHz high-frequency ultrasound(p<0.001)and 50 MHz high-frequency ultrasound(p<0.001)were the relevant factors for predicting the efficacy of flat port-wine stains.(7)Multivariate analysis by multi-classification ordered Logistic regression showed that the density values measured by 20 MHz high-frequency ultrasound(β=1.223>0,95%CI= 1.9～6.07,p<0.001)and 50 MHz highfrequency ultrasound(β=0.968>0,95%CI=1.685～4.111,p<0.001)were the relevant factors for predicting the efficacy of flatport-wine stains.The higher the density value,the better the efficacy.(8)Using 20 MHz highfrequency ultrasound to measure the density value of flat port-wine stains skin lesions accounted for 75% of the invalid group;The predicted effective group accounted for 92.5%.The prediction markly effective group accounted for 50% of the actual ratio;Using 50 MHz high-frequency ultrasound to measure the density value of flat port-wine stains skin lesions accounted for 58.3% of the invalid group.The predicted effective group accounted for 87.5% of the actual ratio;The prediction markly effective group accounted for 50% of the actual ratio.Conclusions: In this study,high-frequency ultrasound detection showed that the thickness of skin lesions in flat port-wine stains was greater than that in adjacent normal skin,and the density of dermis was smaller than that in adjacent normal skin.The dermal density measured by high-frequency ultrasound was positively correlated with the therapeutic effect of laser,among which the density measured by 20 MHz high-frequency ultrasound was more strongly correlated.It is suggested that high-frequency ultrasound can be used to guide the clinical treatment of port-wine stains,among which 20 MHz highfrequency ultrasound may have better clinical predictive value.