Digital Imaging and Communications in Medicine (DICOM)

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Chapter 13 DICOM and Teleradiology
ner in hospital B changes its IP address, and the DICOM printer in hospital C
runs out of film?” Most importantly, this question is not about any fail-over or
backup policies you might have and certainly should implement. This question
is about untying the parts of your expanding workflow as much as possible.
You cannot scale a project that depends on the size of a filing cabinet in reading
room A.
13.8
Conclusion
Summarizing technical and DICOM-related aspects of teleradiology, we can, at
least initially, limit them to the most principal three: image transmission speed,
reliable networking, and display quality. They are directly related. The only way
to transmit images faster implies better networks and the use of lossy image
compression (see 6.2.2), which can potentially create image artifacts and result
in the loss of fine details. The quality of viewing monitors also adds to the image
display quality, but the authority of selecting appropriate monitors remains
more in the administrative domain.
Several popular solutions designed to avoid overuse of lossy compression
and to make image downloads over networks more manageable have been adopted
in teleradiology:
1. Thumbnails. Smaller copies of images (usually also one image per series)
are presented to the remote radiologist. The radiologist decides what he
wants to download by clicking on specific thumbnails.
2. Filtering key images. This is done by trained technologists who might remove
the least important/informative images, thereby excluding them from
transmission. Only selected images are then sent for remote reading.
3. Image postprocessing and reconstructions. These are performed by trained
technologists who replace large image volumes with more compact, postprocessed
representations. A reduced set of postprocessed images is then
sent for remote reading.
Reliable teleradiology networking requires dynamic, self-adjustable, and selfhealing
networks. This part can be strengthened only with appropriate changes
in the current static DICOM design. Imagine one of the simplest tasks in a
dynamic network environment: enumerating currently active DICOM nodes
to see which ones are working and can be used. The most natural way would
be to C-Echo all network nodes and count those that replied. But many static
DICOM nodes will not accept C-Echo from unknown AEs; they will respond
only to a few privileged applications from their white lists. As a result, if we
want to write an application that finds the optimal DICOM path on a complex
DICOM network, we won’t be able to do this with the current DICOM. The
same is true for network-wide C-Find (searching for data on a network, not on
an archive), and in general for all DIMSE relaying, for continuing interrupted