Digital Imaging and Communications in Medicine (DICOM)

18.2 Naive Questions Physicians Like to Ask and Salesmen Like to Brag About
18.2
Naive Questions that Physicians
Like to Ask and Salesmen Like to Brag About
18.2.1
Do I Get the Original Image Resolution if I Buy Your PACS?
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Sorry, but this question is naïve and meaningless at the same time. As long as
the PACS is DICOM-compliant (which is always the case) it will not in any way
attempt to change the image resolution. If your CT image was acquired as a
512×512 pixel matrix with 2 bytes/pixel grayscale, it will always stay that way.
This is one of the reasons we have DICOM, in fact.
The only thing that can affect the image resolution is lossy image compression
(see 6.2.2). No, it will not change the number of pixels either, but it can
introduce compression artifacts, sometimes making the images look less sharp
(reducing your perceptual resolution, if you will). But in DICOM-compliant
systems, the default image transfer format is always uncompressed; that is, you
will get exactly the same image as was first acquired. Compression will be enabled
only if you want to do so.
Moreover, your potential PACS vendor has already obtained their 510-K
premarket approval from the US Food and Drug Administration (FDA), thus
committing to maintaining the original image quality. According to FDA requirements,
images that undergo any quality-degrading modifications (such as
lossy compression) should be clearly labeled as such when they appear on the
screen.
Variations of this question might include “Can you show color images?” or
“Can you show large X-Rays?” and so on. They must show, because of DICOM,
and not because of their groundbreaking technology.
18.2.2
Is Your System Web-Based?
Do not ask it this way. Ask instead whether the system can run in a Web browser.
This is the true meaning of Web-based. If they reply “yes”, ask for a demonstration.
You should see their entire system running as a plug-in within a Webbrowser
window (not next to it, and not in another window – see Fig. 96).