title: Effect of visualization display colour on polyp conspicuity at virtual colonoscopy.
abstract: OBJECTIVE
  To investigate the effect of different colour three-dimensional (3D) displays on polyp detection at virtual colonoscopy (VC).
  
  
  METHODS
  Five VC trained observers were shown "brief flashes" (lasting 0.2s) of 125 3D endoluminal image snap-shots, repeated for each of six display colours (750 images total). One hundred images contained a single polyp (diameter range 5-42 mm) and 25 contained no polyp ("normal"). Images were reviewed in random order over five reading sessions, readers recording either normality or presence and location of a polyp. Multilevel logistic regression was used to examine any influence of colour on polyp detection stratified according to polyp size (medium 5-9 mm/large >or=10mm). The kappa statistic was used to assess effect of colour on observer agreement.
  
  
  RESULTS
  Individual reader polyp detection rates ranged between 75-94%. Compared to the default pink "soft tissue" display, the odds of polyp detection were 0.65 (CI 0.41,1.01) for green, 0.82 (0.53,1.30) for blue, 1 (0.63,1.59) for red, 1.12 (0.7,1.79) for monochrome, and 1.15 for yellow (0.72,1.84). Overall, there was no significant difference between the displays (p=0.11). Including normal cases, there was no overall difference in correct case classification between the six colours (p=0.44). The odds of detecting large versus medium polyps was significantly greater for 3/5 observers; odds ratio (OR) 2.84-10.1, although unaffected by display colour (p=0.3).
  
  
  CONCLUSIONS
  The background colour display generally has a minimal effect on polyp detection at VC, although green should be avoided.
authors: Intestinal Imaging Centre, St Mark's Hospital, Harrow, Middlesex, UK. burlingdavid@yahoo.co.uk
authors: D
authors: D
authors: Burling
authors: A
authors: A
authors: Moore
authors: A
authors: A
authors: Gupta
authors: J
authors: J
authors: East
authors: E
authors: E
authors: Tam
authors: P J
authors: PJ
authors: Pickhardt
authors: M
authors: M
authors: Marshall
authors: S A
authors: SA
authors: Taylor
mesh_terms: D003111:Colonic Polyps / Q000000981:diagnostic imaging* / Q000453:epidemiology; D023881:Colonography, Computed Tomographic; D003116:Color; D003626:Data Display / Q000592:standards*; D006801:Humans; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D016017:Odds Ratio; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000592:standards*