HealthImaging has an interesting little article with some ramifications for digital pathology; Radiology: Image display contrast variation negates consistent mammo readings:
A study published in the August issue of Radiology has determined that image display contrast variations account for the differences between digital and film-screen mammography in detecting cancer in the Digital Mammographic Imaging Screening Trial (DMIST).
In DMIST—co-sponsored by the National Cancer Institute (NCI) and American College of Radiology Imaging Network (ACRIN), participants underwent both digital and film-screen mammography between September 2001 and November 2003. The diagnostic accuracy of digital mammography was found to be “significantly greater” than that of film-screen mammography for women with dense breasts, women younger than 50 and pre- and perimenopausal women....
The authors concluded that the “significantly better diagnostic accuracy” of digital mammography over film-screen mammography was most likely due to differences in image contrast, which were “attributable primarily to differences in the display and acquisition characteristics of the mammography devices rather than to reader variability.”
In digital pathology the debate has largely centered on whether digital images are "as good" as viewing slides through a microscope. There are of course ways in which digital images are better; it is easier to view them remotely, archive and retrieval is better, they don't break or fade, and the tools are much better; you can view multiple images at once, view several views of the same slide (including looking at a thumbnail of the entire slide to orient high-magnification views), pan and zoom easily, measure objects accurately, and so on... but few have claimed that digital images are better than viewing through a microscope. Still, the tools to enhance contrast and change color balance are widely available, and could have the same kind of beneficial effect as found in this study.
Stay tuned!
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I find the topic of monitor technology (LCD or other) fascinating. Remember that images could also be modified by a computer prior to viewing.
Clearly, one must look critically at images produce by a combination of three pure colors (RGB) compared to images produced by a typical microscope light bulb.
Secondly, the screen resolution must be addressed. My VGA cell phone display has a resolution of 240 dpi, compared to the 72 dpi of an ordinary desktop computer display. It looks like a printed magazine page. With a 20in display with this resolution -- a whopping 12 Mpixels -- I could zoom in simply by getting closer to the screen. Radiologists are content with 6 Mpixel screen but I think we need more, a lot more.
Thirdly, one must ask if the images, once digitalized, could be modified to make them more readable. Long ago, I found that a dichroic filter on my microscope lamp makes H&E slides more brilliant, with better color contrast. What could we do with a digital filter?
Posted by: Emmanuel M | August 20, 2009 at 01:41 PM