title: Virtual skin biopsy by optical coherence tomography: the first quantitative imaging biomarker for scleroderma.
abstract: BACKGROUND
  Skin involvement is of major prognostic value in systemic sclerosis (SSc) and often the primary outcome in clinical trials. Nevertheless, an objective, validated biomarker of skin fibrosis is lacking. Optical coherence tomography (OCT) is an imaging technology providing high-contrast images with 4 μm resolution, comparable with microscopy ('virtual biopsy'). The present study evaluated OCT to detect and quantify skin fibrosis in SSc.
  
  
  METHODS
  We performed 458 OCT scans of hands and forearms on 21 SSc patients and 22 healthy controls. We compared the findings with histology from three skin biopsies and by correlation with clinical assessment of the skin. We calculated the optical density (OD) of the OCT images employing Matlab software and performed statistical analysis of the results, including intraobserver/interobserver reliability, employing SPSS software.
  
  
  RESULTS
  Comparison of OCT images with skin histology indicated a progressive loss of visualisation of the dermal-epidermal junction associated with dermal fibrosis. Furthermore, SSc affected skin showed a consistent decrease of OD in the papillary dermis, progressively worse in patients with worse modified Rodnan skin score (p<0.0001). Additionally, clinically unaffected skin was also distinguishable from healthy skin for its specific pattern of OD decrease in the reticular dermis (p<0.001). The technique showed an excellent intraobserver and interobserver reliability (intraclass correlation coefficient >0.8).
  
  
  CONCLUSIONS
  OCT of the skin could offer a feasible and reliable quantitative outcome measure in SSc. Studies determining OCT sensitivity to change over time and its role in defining skin vasculopathy may pave the way to defining OCT as a valuable imaging biomarker in SSc.
authors: Division of Rheumatic and Musculoskeletal Diseases, Leeds Institute of Molecular Medicine, University of Leeds, , Leeds, UK.
authors: Giuseppina
authors: G
authors: Abignano
authors: Sibel Zehra
authors: SZ
authors: Aydin
authors: Concepción
authors: C
authors: Castillo-Gallego
authors: Vasiliki
authors: V
authors: Liakouli
authors: Daniel
authors: D
authors: Woods
authors: Adam
authors: A
authors: Meekings
authors: Richard J
authors: RJ
authors: Wakefield
authors: Dennis G
authors: DG
authors: McGonagle
authors: Paul
authors: P
authors: Emery
authors: Francesco
authors: F
authors: Del Galdo
mesh_terms: D001706:Biopsy; D016022:Case-Control Studies; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012595:Scleroderma, Systemic / Q000175:diagnosis / Q000473:pathology*; D012867:Skin / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: Autoimmune Diseases; Outcomes research; Systemic Sclerosis