Applying ADA/ANSI Standard 1094: Impact of image adjustments and display device on subjective assessments

Abstract

<h3>Objective</h3> To examine operator and device factors that impact subjective assessment of digital radiographic image quality. <h3>Study design</h3> The DDQA phantom was used to generate images to assess spatial resolution, contrast perceptibility, and latitude. The phantom was imaged using an XDR size 2 sensor with a Gendex Expert DC intraoral x-ray source (65 kVp, 7.5mA) at 8 exposure times. Five observers analyzed the images in the native XDR software. Observers were allowed to adjust brightness and contrast to facilitate visualization. Images were analyzed in two environments: a diagnostic radiology reading room with lowered ambient lighting and a Dell Ultrasharp monitor, and an intraoral radiographic room with bright ambient light (450 lux) and an HP EliteOne Computer. The optimum exposure, defined as the lowest exposure that provided the highest feature visualization, was recorded. <h3>Results</h3> In the radiology reading environment, observers were able to discern the full latitude of grayscales at all exposure times. The mean optimal exposure was 0.25s for discerning contrast wells and 0.32s for discerning spatial resolution. Scoring the same images in the intraoral radiography room environment yielded identical results. All observers were able to discern the full image latitude, and the identified optimal exposures were unchanged (0.25s for contrast wells and 0.32s for spatial resolution). <h3>Conclusions</h3> We demonstrate that establishing optimal exposure using the DDQA phantom is reliable, with minimal individual variation. Image adjustments cannot compensate for decreased information. Interestingly, room lighting conditions and display device did not change observer assessments of image quality and optimal exposure times when the observers were allowed to manually adjust brightness and contrast of the presented image. This further validates image quality-guided approaches to establish optimal exposure times in dental clinic settings. In ongoing studies, we will study different display models and ambient lighting settings that are more typical of chair-side settings. <b>Statement of Ethical Review</b> Ethical Review or exemption was not warranted for this study