The impact of computer display performance on the quality of digital radiographs: a review

Abstract

Radiography makes an essential contribution to the processes of examination, diagnosis and treatment planning in dentistry. While the use of film-based imaging still predominates in dentistry, digital imaging is gaining wider acceptance and the use of this modality is anticipated to expand in the future. Two concerns associated with this transition have been raised in the literature. The first of these is the dissatisfaction experienced by many dental professionals with quality of digital radiographs when compared to plain film. In addition, there are indications that practitioners feel limited in their understanding of those factors impacting on digital image quality. One key area highlighted in the literature as having a significant influence on digital radiographic quality and interpretation concerns the performance of the display device. Within the last decade, research derived from the fields of medical radiology and physics have demonstrated that suboptimally performing displays degrade image quality, thereby increasing the potential for compromised diagnostic outcomes. In the field of medicine, this has resulted in the establishment of standards applicable to computer displays used in diagnostic radiology. Conversely, limited guidelines exist in the field of dentistry. The aim of this review is to provide an outline of these standards and highlight the important relationship between computer display performance and digital image quality.Keywords: Quality assurance and digital radiology, quality assurance and medical displays. CONCEPT OF THE DIGITAL IMAGING CHAINThe generation of a radiographic image, whether analogue or digital, is consequent to a series of steps. In analogue radiography information is recorded on emulsion-coated film, which then undergoes chemical processing to reveal the latent image. Techniques concerning patient positioning, exposure parameters and image processing all may influence the quality of the final product. Digital imaging is also dependent on these factors with the exception that information collection and processing is undertaken through electronic means.1 The distinct separation of the process of image acquisition, processing and display in digital radiography presents both advantages and disadvantages. With analogue film, alteration of image quality is possible at the time of image acquisition and processing. However, little or no manipulation of the image is possible after chemical processing has been completed. In digital radiography, the opportunity exists to influence and manipulate information at any time after image acquisition. A digital image can be altered as a consequence of the type of computer hardware, software and graphics system employed, or the type of monitor utilized to display the image. The capacity to alter digital images post-processing is also possible, and offers the opportunity to enhance image quality. Conversely, when digital image quality is less than ideal, it can be difficult to determine the precise cause.

The effect of time in use on the display performance of the iPad

“…Primary displays are used when reading images for the purpose of diagnosis, whereas secondary displays are used for reviewing images for purposes other than diagnosis -for example, the review of images by a referring clinician when a radiologist report has been provided. 9 Primary displays are often dedicated medical display devices, whereas secondary displays are often consumer-grade computer displays. An L max of .350 cdm 22 is recommended for primary displays with the Figure 2.…”

“…8 It is also well recognized that display performance will degrade with increasing time in use, which in turn may degrade diagnostic performance. 9 The display characteristics of the iPad have been previously reported. 10 However, there has been no evaluation of the effect of time in use on the display performance of the iPad.…”

Colour in digital pathology: a review

“…This method ensures that each shade of grey in the transition from white to grey is perceptually linear by taking into account the ability of the human visual system for light, dark and chromatic adaption, preventing two shades of grey from being too close together perceptually. Studies have indicated that calibration using DICOM Part 14 GSDF for radiology displays results in better observer performance, and much of the research in digital radiology is based around compliance to these standards …”

Impact of viewing conditions on the performance assessment of different computer monitors used for dental diagnostics

“…To capture the market, dentally configured medical-grade monitors are available that have been engineered to the resolution and grey scale of dental radiographs. 15 16 17 However, conflict is evident throughout the literature regarding their benefit for radiographic diagnostics over off-the-shelf monitors. 2 4 5 6 9 15 16 18 19 20 21 …”