[Insight-developers] dicom time series

[Iván Macía]

Dear Richard,

In order to distinguish 3D images from 2D+t time series we usually check
Image Position Patient. Same Image Position Patient (and Image Orientation
Patient of course) means it is a time series. I have not worked with MR
Phase Contrast myself but other dynamic MR sequences (3D+t) from Siemens
have Temporal Position Identifier (0020,0100) and Number of Temporal
Positions (0020,0105) DICOM tags. Note that these are optional. Otherwise,
you may have a look at some other tags like Acquisition Time or Acquisition
Group but usually it is difficult to find a rule that works for most
vendors.

DicomWorks software has a nice functionality that shows you which DICOM tags
vary among the images of the same series so you can have a look to see if
any of those is valid to identify the different groups you need.

HTH

Ivan

 

-----Mensaje original-----
De: insight-developers-bounces at itk.org
[mailto:insight-developers-bounces at itk.org] En nombre de Richard Beare
Enviado el: viernes, 13 de febrero de 2009 3:30
Para: insight-developers at itk.org
Asunto: [Insight-developers] dicom time series

Hi,
This question relates to the phase constrast dicom series I mentioned
in my last post.

These series are a time series of a single slice. My dicom sorting
seems to be doing the right thing, but the conversion to nifti does
not. The problem is that the time dimension is interpreted as the z
dimension, so sequence appears as a 3d voume, rather than a 4d time
series with a single slice. At present I'm not sure of the dimension
figures that are being passed through the conversion process, so
simply permuting the dimensions might not be advisable.

Has anyone come across issues of this sort when reconstructing time
series? Are there special dicom tags I'm likely to be missing?

These are captured on a 1.5T siemens machine.

Thanks
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