When you retrieve an SR which referenced an Image for example. If you
don't have this image on your disk, you have to make a query/retrieve
on it?? Or transaction Query/Retrieve SR implements the "automatic"
download of the referenced images??
Re: Query/Retrieve SR??
The DICOM standard doesn't provide any "automatic" retrieval of the
images referenced by an SR. The behavior and dependencies of your
application is something you will have to decide yourself. You could
for example build your application around a constraint which says you
would only support visualization/display of SRs with images when your
system had received both the SR and the images it refences. An
alternative would be for your application to go search for images
referenced by the SR and to retrieve them. Several different DICOM
services could be used by your application to do that search/retrieval.
DICOM query/retrieve is the most widely deployed service - available on
many different PACS, workstations. However, the hierarchical nature of
the default DICOM query model, makes it less than ideal for tracking
down individual image instances, especially if the images could
potentially be located in a number of different archives. DICOM Q/R
also tends to require a large number of network interactions when it is
being used to track down individual images. DICOM Relevant Patient
Information Query is another service being developed to provide a
lighter weight/faster query which could be used to track down
referenced images. Finally, a DICOM instance locator service has been
proposed in the DICOM committee to provide a means for applications to
locate DICOM instances by their UIDs without having to use higher level
patient or study level attributes to search for the images. This was
just proposed in the committee in January so I wouldn't look to have it
in the standard before the end of the year and probably not deployed in
operational systems for another year or two after that