Evaluating the diagnostic value of shear wave elastography in early systemic sclerosis: a case-control study

Abstract Systemic sclerosis (SSc) involves progressive fibrosis, with musculoskeletal involvement being common but often assessed using muscle biopsy and magnetic resonance imaging. Shear wave ultrasound elastography (SWE) offers a non-invasive quantitative measure of tissue stiffness that may detect early muscle changes in SSc. This study investigated muscle stiffness using SWE in patients with early SSc, compared findings with healthy controls, and evaluated the diagnostic performance of SWE measurements. In this prospective case-control study, 30 patients with early SSc (disease duration ≤ 3 years) and 30 age- and sex-matched healthy controls underwent SWE assessment of the bilateral rectus femoris, vastus medialis, and vastus lateralis muscles in both longitudinal and transverse orientations. Shear wave velocity (SWV) values were compared between groups. SSc patients showed significantly higher muscle stiffness in the left rectus femoris than controls (2.19 ± 0.43 m/s vs. 1.96 ± 0.35 m/s; p = 0.03), whereas other muscles showed a trend toward increased stiffness without statistical significance. Area under the receiver operating characteristic curve for the left rectus femoris (longitudinal orientation) was 0.67 (95% CI: 0.53–0.81; sensitivity 66.67%, specificity 70%). Intra- and inter-operator reliability was 0.66 to 0.95. In conclusion, SWE is a feasible, non-invasive method to quantify muscle changes in early SSc, identifying the left rectus femoris as significantly stiffer than healthy controls. These findings support the potential utility of SWE for detecting muscle abnormalities in SSc.