Quantification of skin stiffness in patients with systemic sclerosis using real-time shear wave elastography: a preliminary study.

OBJECTIVES: To assess the diagnostic value of shear wave elastography (SWE) quantification in patients with systemic sclerosis (SSc) and healthy controls.

METHODS: Skin elastic modulus (E) values and thicknesses were measured at 6 skin sites between the SSc (n=37) and control (n=37) groups. Thickness and E values were converted into T- and E-scores, to allow skin thickness and stiffness of different regions to be quantified based on a single standard. T- and E-scores were compared with the modified Rodnan skin score (mRSS).

RESULTS: E values were significantly higher in SSc patients than healthy controls at all measured sites (p<0.001), whereas skin thickness increased significantly only at fingers and forearms (p<0.001). E-score analysis revealed mRSS differences within 1.0 at most sites, while T- score evaluation only showed differences between mRSS 0 and mRSS 1 at fingers. Interestingly, mRSS correlated more closely with skin stiffness (r=0.889, p<0.001) than skin thickness (r=0.465, p=0.002).

CONCLUSIONS: In patients with SSc, SWE is more sensitive to detect subtle skin changes than B-mode ultrasound (US), and reflect the degree of skin involvement. As a non-invasive and operator-independent technique, SWE may provide a new and valuable method to evaluate the degree and changes of skin involvement in SSc patients.