Effect of visualization display colour on polyp conspicuity at virtual colonoscopy.
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.
Burling
D
D
Intestinal Imaging Centre, St Mark's Hospital, Harrow, Middlesex, UK. burlingdavid@yahoo.co.uk
Moore
A
A
Gupta
A
A
East
J
J
Tam
E
E
Pickhardt
P J
PJ
Marshall
M
M
Taylor
S A
SA
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*