A Preliminary Study Of Conventional Ultrasound Combined With Elastography In Evaluating The Active Lesions Of Juvenile Localized Scleroderma

Objective:The changes of thickness,echo and blood flow of active lesion skin and subcutaneous tissue in juvenile localized scleroderma(JLS)were evaluated by conventional ultrasound,and the stiffness of JLS active lesion skin was quantitatively evaluated by ultrasound elastography,and the evaluation value of ultrasound elastography on the severity of JLS active lesion was discussed.Methods: This is a cross-sectional single center study.A prospective analysis was conducted on 27 children with JLS(46 active lesions)diagnosed clinically and pathologically in the Department of Dermatology or Rheumatic Immunology Department of X-Hospital from March 2021 to December 2022.The localized scleroderma assessment tool(Lo SCAT),conventional ultrasound and ultrasonic elastography were used to evaluate the lesioned skin and its symmetrical normal skin(hereinafter referred to as the normal side).Lo SCAT includes modified local scleroderma skin severity index(MLo SSI)and localized scleroderma damage index(Lo SDI).The thickness,echo and blood flow of the lesioned and normal skin and subcutaneous tissue were evaluated by conventional ultrasound,the stiffness of the lesioned and normal skin was evaluated by shear wave elastography(SWE),and the stiffness of the lesioned and surrounding normal skin was evaluated by strain elastography(SE).The differences of thickness,echo and blood flow of skin and subcutaneous tissue between the lesioned and the normal side were compared.The differences of Young’s modulus and shear wave velocity of skin between the lesioned and the normal side were compared.The elastic strain ratio of the lesioned and the surrounding normal skin was measured.The correlation between Young’s modulus and MLo SSI,Lo SDI clinical score of lesioned skin was analyzed.Results: There were 46 active lesions in 27 children with JLS.Comparison of conventional ultrasound between lesioned skin and normal skin,there was no significant difference in skin thickness between 46 JLS lesions and normal skin(P > 0.05),the subcutaneous tissue thickness of 46 JLS lesion sides was thinner than that of the normal side,and the difference was statistically significant(P < 0.05);Among the 46 lesions,the skin echo of 32 lesions was stronger than that of the normal side,and the echo of subcutaneous tissue of 25 lesions was stronger than that of the normal side;The blood flow signal of 9 lesioned skin was higher than that of normal skin,and the blood flow signal of subcutaneous tissue of 5lesions was higher than that of normal skin.Comparing the ultrasonic elastography between the lesioned skin and the normal skin,the Young’s modulus and shear wave velocity of 46 lesioned skin were higher than those of the normal side,and the difference was statistically significant(P < 0.05);The elastic strain rate ratio of all lesioned skin to surrounding normal skin is greater than 2.The Young’s modulus of the lesioned skin of 27 children was moderately correlated with MLo SSI score(r = 0.63-0.69,P < 0.05),but not with Lo SDI score(r = 0.27-0.33,P > 0.05).Conclusion: The sonographic characteristics of JLS active lesions were evaluated by conventional ultrasound,the skin stiffness of JLS lesions was quantitatively evaluated by ultrasonic elastography,and the severity of JLS activity was evaluated by MLo SSI clinical score,which can provide a certain reference value for the clinical treatment of JLS.