BACKGROUND Measurement of skin involvement is essential for the diagnosis and assessment of prognosis and disease progression in systemic sclerosis (SSc). The modified Rodnan skin score (mRSS) is the gold standard measure of skin thickness, but it has been criticised for the lack of objectivity, poor inter-observer reproducibility and lack of sensitivity to change. Recently, shear-wave elastography (SWE) emerged as a promising tool for the objective and quantitative assessment of the skin in SSc patients. However, no studies have evaluated its sensitivity to change over time. OBJECTIVE To assess changes in skin stiffness in SSc patients using SWE during a 5-year follow-up. METHODS Skin stiffness [i.e. shear-wave velocity values (SWV) in metres per second] was assessed by SWE ultrasound (using virtual touch image quantification) at the 17 sites of the mRSS, in each participant, at baseline and follow-up. mRSS was performed at both time points. Differences between groups were analysed using the related-samples Wilcoxon signed-rank test and the Mann-Whitney U test. RESULTS We included 21 patients [85.7% females; mean age 56.3 (10.4) years at baseline, 57.1% with limited SSc] and 15 healthy controls [73.3% females; mean age 53.6 (14.1) years)]. The median follow-up was 4.9 (0.4) years. Skin stiffness decreased significantly at all Rodnan sites (p ≤ 0.001) (except in the fingers), in SSc patients, over time. The same phenomenon occurred in controls, but to a lesser degree, in terms of percentage change. The percentage reduction in skin stiffness varied in the different Rodnan sites and in different phases of the disease. In addition, SWV values also decreased significantly in 15/16 skin sites with local normal Rodnan at baseline, whereas local Rodnan skin score only changed significantly in the upper arm (p = 0.046) and forearm (p = 0.026). CONCLUSION This study provides first-time evidence suggesting that skin SWV values are more sensitive to change over time than mRSS and reduce significantly over time in SSc and normal controls.

中文翻译：

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系统性硬化症随着时间的流逝，皮肤的改善多少归因于正常衰老？剪切波弹性成像的前瞻性研究。

背景技术皮肤受累的测量对于系统性硬化症（SSc）的预后和疾病进展的诊断和评估是必不可少的。改良的Rodnan皮肤评分（mRSS）是皮肤厚度的金标准量度，但因缺乏客观性，观察者之间的可重复性差和对变化的敏感性而受到批评。最近，剪切波弹性成像（SWE）成为一种有前途的工具，可用于对SSc患者的皮肤进行客观和定量的评估。但是，没有研究评估其随时间变化的敏感性。目的在5年的随访中评估使用SWE治疗SSc患者的皮肤僵硬程度的变化。方法皮肤僵硬[即 在基线和随访时，在每个参与者的mRSS的17个部位，通过SWE超声（使用虚拟触摸图像定量）评估了以米/秒为单位的剪切波速度值（SWV）。在两个时间点都进行了mRSS。使用相关样本Wilcoxon秩和检验和Mann-Whitney U检验分析两组之间的差异。结果我们纳入了21例患者[85.7％女性；基线时的平均年龄为56.3（10.4）岁，SSc受限者为57.1％]和15名健康对照者[女性为73.3％；平均年龄53.6（14.1）岁]]。中位随访时间为4.9（0.4）年。随着时间的推移，SSc患者的所有Rodnan部位的皮肤僵硬程度均显着降低（p≤0.001）（手指除外）。控件中发生了相同的现象，但百分比变化较小。在不同的Rodnan部位和疾病的不同阶段，皮肤僵硬的减少百分比有所不同。此外，基线时局部Rod Rodnan正常的15/16个皮肤部位的SWV值也显着降低，而局部Rodnan皮肤评分仅在上臂（p = 0.046）和前臂（p = 0.026）上有明显变化。结论这项研究首次提供了证据，表明皮肤SWV值随时间的变化比mRSS更敏感，并且在SSc和正常对照中随时间的推移会明显降低。