I saved the DICOM files received from the scanner as binary data and
then processed them and then converted these files into DICOM files
using IDL. When I push the DICOM files to PACS, all 3D data sets are
fine. I can view them clearly.
I have a 4D data sets (512x512x7x60). I can convert them into DICOM
files and when I push them to PACS, I can only see the 1st seven
slices. The total number of slices for that series is 7 instead of 420
slices. However, I can view all 420 slices on the other DICOM viewers
like Acculite, ImageJ, DICOM Works and MRIcro.
I checked all the header information. I could not find the reason. Can
anybody tell me what header information should I change to make it a 4D
data on PACS.
What are your four dimensions? 512x512 looks pretty obvious rows and
colums (e.g. X and Y) but 7x60? Are you talking about raw acquisition
data which is reconstructed into 60 time steps, each time step
consisting of 420 * 512x512 image slices?
Really more to the point, what modality, DICOM SOP Class, and PACS are
you talking about? Based on your subsequent discussion of 420 slices,
one presumes talking about CT or MR. When processing and converting to
DICOM the device would likely break apart into individual image slice
objects (unless you know they are in fact using one of the newer
enhanced CT or enhanced MR multiframe objects). This would explain
why external applications correctly receive and recombine the
individual images into the expected data organization. On the other
hand if your "PACS" is a machine/workstation associated with device
itself, perhaps it is not actually turning the raw data into DICOM
images and is instead sending one large proprietary file? Perhaps you
are running into a maximum size or index problem in that format?
Can anybody suggest some DICOM tags that are critical for 4D data sets.
Sorting out the "dimensions" of a set of DICOM images is in
general a non-trivial problem, but is largely a question of
conforming to patterns of spatial and timing information that
the receiver can make sense of retrospectively.
For example, do all the images at different times but the same
location in space have the same value for Image Position (Patient)
and Image Orientation (Patient) ? They should.
Do all the images acquired at or close to the same time have the
same or similar Acquisition Time value, sufficiently different
from the Acquisition Time of other images ? It is in general
quite hard for the receiver to sort out what belongs in the
same "time slot" when there are small differences in time
that don't matter and larger differences that do, if you get
Some receivers are just not capable of this sort of re-sorting,
and just sort by Instance Number or spatial position alone;
others expect the separate "time slots" to be in separate
series. Others pay more attention to Content (Image) Time
rather than Acquisition Time, though they probably shouldn't.
These are some of the reasons that the new enhanced family of
MR image objects are multi-frame, have unambiguous timing
information, and have explicit dimensions. The sooner folks
start to use these instead, and the sooner PACS vendors
support them, the better.
Can you put these on an ftp site somewhere that I can take a
look at them ? It is possible that you have just left out
something or made a simple error if you reconstructed them
yourself, or used some research tool to do it. I can make
a site available to you if you do not have one.
Thanks a lot for your time,