The diagnostic value and clinical relevance of high frequency ultrasound and shear wave elastography in systemic sclerosis: an observational monocentric study

To unravel the features of skin involvement in patients with systemic sclerosis (SSc) by high frequency ultrasound (HFU) and shear wave elastography (SWE). To assess the ultrasound capabilities to distinguish SSc patients from healthy controls (HCs). We recruited a cohort of SSc patients in this cross-sectional study. HFU and SWE were used to quantify skin thickness and skin stiffness. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic capabilities of ultrasound in SSc. The correlation analysis was used to evaluate the clinical relevance of ultrasound measurements in SSc. 20 consecutive SSc patients and 20 age-, gender- and body mass index-matched HCs were included. The skin thickness and stiffness were significantly greater in SSc patients compared with HCs. Patients with high disease activity had higher skin thickness and stiffness compared with patients with low disease activity. The area under the ROC curve (AUC) of the dorsum of middle fingers assessed by HFU was 0.847 (95% CI, 0.761-0.933). The AUC of the forearms and dorsum of hands assessed by SWE were 0.909 (95% CI, 0.829-0.989) and 0.879 (95% CI, 0.807-0.951). Further, the combined HFU and SWE tests displayed the best diagnostic performance with an AUC of 0.980 (95% CI, 0.939-1.000). A significant positive correlation between the ultrasound measurements and the modified Rodnan skin score (mRSS) was observed. The application of ultrasound can assist with disease diagnosis, it is necessary to develop a standard operating protocol to help with future implementation of ultrasound in SSc.