title: Computerized nailfold video capillaroscopy--a new tool for assessment of Raynaud's phenomenon.
abstract: OBJECTIVE
  To develop a computer based nailfold video capillaroscopy system with enhanced image quality and to assess its disease-subgroup resolving power in patients with primary and secondary Raynaud's phenomenon (RP).
  
  
  METHODS
  Using frame registration software, digitized video images from the microscope were combined to form a panoramic mosaic of the nailfold. Capillary dimensions (apex, arterial, venous, and total width) and density were measured onscreen. Significantly, the new system could guarantee analysis of the same set of capillaries by 2 observers. Forty-eight healthy control subjects, 21 patients with primary RP, 40 patients with limited cutaneous systemic sclerosis (lcSSc), and 11 patients with diffuse cutaneous SSc (dcSSc) were studied. Intra- and interobserver variability were calculated in a subset of 30 subjects.
  
  
  RESULTS
  The number of loops/mm was significantly lower, and all 4 capillary dimensions significantly greater, in SSc patients versus controls plus primary RP patients (p < 0.001 for all measures). When comparing control (+ primary RP) patients with SSc patients (lcSSc + dcSSc) the most powerful discriminator was found to be the number of loops/mm. Results for intra- and interobserver reproducibility showed that the limits of agreement were closer when both observers measured the same capillaries.
  
  
  CONCLUSIONS
  The key feature of the newly developed system is that it improves reproducibility of nailfold capillary measurements by allowing reidentification of the same capillaries by different observers. By allowing access to previous measurements, the new system should improve reliability in longitudinal studies, and therefore has the potential of being a valuable outcome measure of microvessel disease/involvement in clinical trials of scleroderma spectrum disorders.
authors.affiliation: University of Manchester Rheumatic Diseases Centre, Hope Hospital, Salford, UK.
authors.forename: Marina E
authors.initials: ME
authors.lastname: Anderson
authors.forename: P Danny
authors.initials: PD
authors.lastname: Allen
authors.forename: Tonia
authors.initials: T
authors.lastname: Moore
authors.forename: Val
authors.initials: V
authors.lastname: Hillier
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Taylor
authors.forename: Ariane L
authors.initials: AL
authors.lastname: Herrick
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002196:Capillaries / Q000502:physiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D020678:Microscopic Angioscopy / Q000295:instrumentation* / Q000379:methods* / Q000706:statistics & numerical data; D018715:Microscopy, Video; D008875:Middle Aged; D009262:Nails / Q000098:blood supply; D015588:Observer Variation; D011928:Raynaud Disease / Q000175:diagnosis* / Q000503:physiopathology; D012595:Scleroderma, Systemic / Q000175:diagnosis / Q000503:physiopathology; D012984:Software