Influence of the digital image display monitor on observer performance

Objective: To assess the influence of the display monitor on observer perfo rmance. Material and methods: Artificial enamel lesions were created in 40 extracte d teeth at random using 1/4 and 1/2 round burs. Teeth were mounted in denta l stone blocks to simulate a hemidentition. Approximate exposures were reco rded at 70 kVp using a Digota (Soredex, Orion Corp, Helsinki, Finland) digi tal imaging system, calibrated to achieve optimum density. Six dentists rat ed each image on a five-point scale for the presence or absence of a lesion . Radiographic images were viewed on the following monitors: (1) AlphaScan 711 (Sampo Corp.); (2) Multiscan 17 Se II(Sony Electronics Inc.); (3) DS 20 00 (Clinton Electronics Corp.) and (4) Latitude CP Laptop (Dell Computer Co rp.). Raters were allowed to magnify and to adjust density and contrast of each image at will. Receiver Operating Characteristic (ROC) analysis was pe rformed and curves were plotted for each image. Data was subjected to repea ted measures analysis of variance and ordinal logistic regression to test f or significance between variables and to determine odds ratios. Results: Mean ROC curve areas ranged from 0.8728 for the Sampo monitor to 0 .8395 for the Sony. Repeated measures analysis of variance showed significa nt differences between observers (P < 0.0001), lesion size (P < 0.0001), ex aminer/monitor interaction (P < 0.033) and examiner/block interaction (P < 0.013). However, no significant difference was found between monitors. Conclusion: This study suggests that observer performance is independent of the visual characteristics of the display monitor.