Reduction in size of digital images: does it lead to less detectability or loss of diagnostic information? .
OBJECTIVE
To analyse the effect of reduction in size of digital images on diagnostic outcome.


METHODS
A series of 100 Visualix III (Gendex Dental Systems, Milano, Italy; Dentsply, Des Plaines, IL, USA) images was made of size 10 and 15 endodontic files in upper and lower (pre)molars. Three forms of image were created: (a) the original images, (b) reduced to one-half (containing one-quarter of the information of the original, and (c) zoomed-in, half-size images (magnification 2:1; original image size but with only one-quarter of the original information). Seven radiologists were asked to rate the position of the tip of the file, using a five-point confidence scale. ROC data were analysed by means of MANOVA statistics.


RESULTS
A significant difference was found between the three image modalities for both size 10 (P < 0.005), and size 15 (P < 0.021) files.


CONCLUSIONS
Reduction in size of digital images may cause less detectability as well as loss of diagnostic information.
Versteeg
C H
CH
Department of Oral Radiology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands.
Sanderink
G C
GC
Lobach
S R
SR
van der Stelt
P F
PF
D016287:Computer Peripherals; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D006801:Humans; D008838:Microcomputers; D015999:Multivariate Analysis; D015588:Observer Variation; D011786:Quality Control; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D019252:Radiography, Dental, Digital / Q000295:instrumentation / Q000379:methods* / Q000592:standards