title: The use of portable radiometry to assess Raynaud's phenomenon: a practical alternative to thermal imaging.
abstract: OBJECTIVE
  To compare the performance of a portable radiometer with thermal imaging and to assess the potential for radiometry to provide a practical alternative for assessing vascular responsiveness in Raynaud's phenomenon (RP).
  
  
  METHODS
  Subjects comprised 18 patients with diagnosed RP and 19 non-RP subjects. A thermal imager (Starsight) and a portable radiometer (Cyclops) measured digital temperature at baseline and the subsequent drop and rise in temperature following a cold challenge test.
  
  
  RESULTS
  The intra-class correlations between the two instruments for all three measures exceeded 80%. The overall performance of each instrument was almost the same, the Starsight thermal imager correctly classifying 84% of subjects as RP or non-RP and the Cyclops portable radiometer correctly classifying 86% of subjects. The sensitivity of the thermal imager was 83%, compared with 89% for the portable radiometer; the specificity of both instruments was 84%. The positive and negative predictive values of the thermal imager were 83 and 84% respectively, and those for the portable radiometer were 84 and 89%.
  
  
  CONCLUSIONS
  The two instruments performed equally well and the differences between them in their absolute measurements did not influence their ability to detect RP. Portable radiometry provides a practical, cheap, accurate and reliable alternative to thermal imaging and has the potential to be used in range of clinical and epidemiological settings.
authors.affiliation: Twin Research and Genetic Epidemiology Unit, St Thomas' Hospital, London, UK.
authors.forename: L F
authors.initials: LF
authors.lastname: Cherkas
authors.forename: K
authors.initials: K
authors.lastname: Howell
authors.forename: L
authors.initials: L
authors.lastname: Carter
authors.forename: C M
authors.initials: CM
authors.lastname: Black
authors.forename: A J
authors.initials: AJ
authors.lastname: MacGregor
mesh_terms: D000293:Adolescent; D000328:Adult; D003080:Cold Temperature; D005260:Female; D006801:Humans; D008875:Middle Aged; D011874:Radiometry / Q000295:instrumentation*; D011928:Raynaud Disease / Q000175:diagnosis*; D012039:Regional Blood Flow; D013817:Thermography