AB0617 OPTICAL COHERENCE TOMOGRAPHY IN THE ASSESSMENT OF SKIN FIBROSIS IN SYSTEMIC SCLEROSIS: A CROSS-SECTIONAL STUDY

Abstract

Background:Previous studies have shown that Optical Coherence Tomography (OCT) is a reliable biomarker of skin fibrosis and significantly correlates with the severity of the skin involvement in Systemic Sclerosis (SSc)1,2.Objectives:Aim of this cross-sectional study was to evaluate the performance of skin OCT to discriminate between SSc and healthy controls (HC) and to compare results with the current gold standard, the modified Rodnan skin score (mRss), in a different SSc study cohort.Methods:Dorsal forearm skin of consecutive diffuse cutaneous SSc (dcSSc) patients and matched-HC was scanned by an investigator blinded to the clinical data using Vivosight scanner (Michelson Diagnostics, Kent, UK). Minimum Optical Density (MinOD), Maximum OD (MaxOD) and OD at 300 micron-depth (OD300) were measured. Clinical involvement was assessed by a blinded operator using the mRss and results were compared with imaging data. Statistical analysis was performed using GraphPad Prism software V.7.0.Results:A total of 88 OCT images were obtained from 22 dcSSc patients [20 Female, mean age 49 (±11) years, 12 with < 5 years disease duration) and 22 HC (20 Female, mean age 50.7 (±6.7) years]. All OCT measures (MinOD, MaxOD and OD300) were significantly lower in SSc patients than in HC (p=0.011, p<0.0001, p<0.0001 respectively). MaxOD and OD300 were significantly different between the four groups (0-3) of patients based on the mRss at the site of analysis (p=0.035, p=0.001 respectively). Skin OCT showed a good performance in discriminating SSc skin vs HC (overall AUC 0.72, 0.8 and 0.89 for MinOD, MaxOD and OD300 respectively).Conclusion:These results confirm in a cohort different from those of the previous studies that skin OCT is able to reflect the severity of skin involvement in SSc. Longitudinal studies are needed to validate its potential as surrogate outcome measure of skin fibrosis in SSc patients.