In vitro perception of low-contrast features in digital, film, and digitized dental radiographs: a receiver operating characteristic analysis.
OBJECTIVE
To compare experimentally the image quality of charged-coupled device (CCD)-based digital, flatbed scanner digitized, and dental film radiographs.


METHODS
High-contrast standardized radiographs of an aluminum step wedge containing boreholes were obtained on dental radiographic film (F) and a CCD receptor (D). Digitization (S) was done with a flatbed scanner. Each radiograph was separated into 23 single images, 18 of which showed a dark spot. Thirty observers indicated their confidence on the visibility of the spots for a receiver operating characteristic (ROC) analysis.


RESULTS
Mean Az values (area beneath the ROC curves) differed significantly (P < .05), being highest for D (Az = 0.76), followed by F (Az = 0.71) and S (Az = 0.60). Mean sensitivity of S (0.45) was significantly (P = .000) lower than for D (0.66) and F (0.67).


CONCLUSIONS
The difference between modality D and F was small. However, the inferior performance of S images, particularly in dark regions, could be clinically relevant.
Grassl
Ulrich
U
Department of Oral Surgery and Radiology, Dental School of the University of Basel, Basel, Switzerland. uligrassl@web.de
Schulze
Ralf Kurt Willy
RK
D003287:Contrast Media; D019047:Phantoms, Imaging; D012372:ROC Curve; D011856:Radiographic Image Enhancement; D011861:Radiography, Dental / Q000295:instrumentation* / Q000379:methods*; D019252:Radiography, Dental, Digital; D012666:Semiconductors; D012680:Sensitivity and Specificity; D014962:X-Ray Film; D014963:X-Ray Intensifying Screens
D003287:Contrast Media