MULTI-FRAME and Secondary Capture
Chad Evans
I have a couple of questions about Multi-Frame images.
1. Can a Secondary Capture image contain multiple frames? If it is a
possibility as far a the standard is concerned, how common is it?
2. What is the correct way to determine if an image is multiframe? I'm using
tag 0028, 0008 (Number of Frames). If it is in the DICOM I assume the image
is multi-frame. I have run into a couple of cases where the DICOM is sent
with only the 0028, 0008 of the multi-frame module set to 1. In one case I
found the tag in a single frame US SOP. Is that legal DICOM?
Thanks in advance.
Chad Evans
David Clunie
Chad Evans wrote:
> I have a couple of questions about Multi-Frame images.
>
> 1. Can a Secondary Capture image contain multiple frames? If it is a
> possibility as far a the standard is concerned, how common is it?
There is a whole new family of multi-frame SC image SOP Classes which
can be used for this purpose. They are just new, so they are not yet
in common use. One of the first major applications is likely to be
by the cardiac NM vendors who want to be able to capture the results
of processing.
The original SC SOP Class is absolutely single frame and under no
circumstances should you try to squeeze a multi-frame image in there.
> 2. What is the correct way to determine if an image is multiframe? I'm using
> tag 0028, 0008 (Number of Frames). If it is in the DICOM I assume the image
> is multi-frame. I have run into a couple of cases where the DICOM is sent
> with only the 0028, 0008 of the multi-frame module set to 1. In one case I
> found the tag in a single frame US SOP. Is that legal DICOM?
One way is to check the SOP Class ... some SOP Classes contain
the appropriate attributes and others don't.
Expediently however, if Number Of Frames is present and not 1, then
obviously there is more than one frame; if Number of Frames is 1 or
is absent, then there is exactly one frame (whether it be the only
frame of a single-frame SOP class, or the one frame of a multi-frame
SOP class can only be determined by also looking at the SOP Class UID).
Clearly it is quite legal to have a one-frame image of a multi-frame
SOP class; NM and XRF are typical examples; even XA images are sometimes
just one frame. In the US case, one could have just one frame of the
US Multi-frame SOP Class.
Even for a single frame object, there is no prohibition on (0028,0008)
being present (as a 'standard extended SOP class'), but clearly it
could only have a value of 1. One could imagine a US implementation
for example, the built US SF and MF objects with the same set of
attributes, using the SF SOP Class UID if and only if (0028,0008) was
1, but not removing the (0028,0008) and other related attributes.
david