Original articleTechnology and Perception in the 21st-Century Reading Room
Section snippets
Perception and the transition from film to digital
Much of the early research in radiologic image perception centered on ways to better understand how and why radiologists made errors and why there is so much interobserver and intraobserver variation [1, 2, 3, 4]. Examinations of visual search patterns using eye-position recording techniques revealed much about the source of reader errors as well as the role of experience in image perception [5, 6, 7, 8, 9]. As the transition from film to the digital display of radiographic images began to take
Perceptual optimization of soft-copy image display
The question that lingered after the early equivalence studies was how to optimize soft-copy displays to yield the best possible display of images without introducing too much burden on radiologists in the form of excessive image processing to render images in an acceptable way. The majority of the early display evaluations were done with cathode ray tube (CRT) displays, and much has been written on how to physically characterize and calibrate them [14, 15]. Today, liquid crystal displays
Display luminance
For example, one study compared diagnostic accuracy as a function of display luminance and also recorded eye position to determine if luminance affected the visual search patterns of radiologists [21]. The study used a high-performance, monochrome CRT (140 ftL) with another high-performance display that had a 60% decrease in luminance (80 ftL). Performance in the higher luminance condition was better than in the lower luminance condition, although statistical significance was not achieved. The
Display calibration
Another crucial display parameter that has been found to influence both perception and performance is how a soft-copy display is calibrated. As soon as soft-copy displays began to be used, it was noticed that the same image displayed on one display often looked very different when displayed on another device. Even when an image was displayed on the same device, it could look different at different times. To address this issue, the Digital Imaging and Communications in Medicine (DICOM) Grayscale
CRTs vs LCDs
Every type of display has some advantages and some disadvantages. The CRT was the major electronic display for years before LCDs matured enough to be used for the primary interpretation of radiographic images. Cathode ray tubes are certainly well-suited for radiologic interpretation in terms of spatial resolution and luminance, but they are also bulky and have curved glass surfaces that produce reflections (even with antiglare coatings, there are some reflections) [23] and increase veiling
Compensating for display deficiencies
Luminance, calibration technique, and monitor technology are just a few of the physical characteristics of soft-copy displays that have been shown to influence diagnostic accuracy and the visual search performance of radiologists. As technology improves and as new display technologies are developed, further characterization, optimization, and evaluation of displays will have to take place to ensure that diagnostic accuracy is not affected negatively. In the meantime, ways to improve current
Image processing and interobserver variability
Many studies carried out in the laboratory setting generally show improved performance (of varying degrees) when a given image processing tool is implemented. Some of the more successful and often-used tools are those that use edge enhancement. For example, Goo et al [34] had radiologists review a series of neonatal chest images before and after edge enhancement was applied and found that the edge enhancement improved significantly the visualization of pneumothoraces, vascular catheters, the
21st-century perception opportunities
It is clear that digital reading rooms have already changed dramatically the image interpretation process and presented the opportunity for a wide variety of new tools for radiologists to use for interacting with and manipulating displayed image data. It has already been noted that the display medium itself is also likely to continue to change as new technologies emerge, and the tools that radiologists have will also continue to develop and change. One thing driving the need to develop more
Summary
Radiologists practicing 10 years from now will in all likelihood be working in a very different environment than today’s radiologists. Analog film will be a rare commodity compared with today, used for the most part for old comparison studies. There are likely to be new types of digital images, acquired using different technologies than exist today, and processed in ways that have yet to be conceived. Molecular imaging will surely have a huge impact on the types of studies being done and the
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