Assessment of skin stiffness in systemic sclerosis using optical coherence elastography: A comparative study with histology and clinical parameters.

Abstract

Systemic sclerosis (SSc), or scleroderma, is an autoimmune disorder marked by increased mortality due to excessive collagen accumulation in the body. The modified Rodnan Skin Score (mRSS) is the standard for assessing dermal thickening in SSc but shows high observer variability. Optical coherence elastography (OCE) is a promising alternative for evaluating skin involvement in SSc, though comprehensive comparative studies with histological and clinical assessment are lacking. We evaluated OCE's face (SSc versus healthy skin), construct (correlation to mRSS), and criterion (correlation with histology) validities in 20 control and 55 SSc patients, with assessments on the finger, hand, and forearm. Assessors were blinded to results in the other domains, and OCE was performed completely contact free at ∼500 Hz, 1 kHz, 5 kHz, and 10 kHz stimulation. There was a significant difference in OCE measurements between control and SSc skin at all examined locations (face validity). However, there was a weak to moderate correlation between OCE and mRSS at certain frequencies (construct validity). Additionally, OCE exhibited weak to moderate correlations with histological parameters. Although OCE demonstrated strong face validity, its construct and criterion validity were moderate at best, highlighting the need for further development. This research is the most exhaustive comparison of OCE against clinical and histological markers of skin involvement in SSc. The results strongly support OCE's face validity, but the weak to moderate construct and criterion validity underline the need for further development. Nevertheless, these results show critical progress towards developing an objective skin assessment tool for SSc.