[Insight-users] Dicom and Image Spacing

[Alexander Schmidt-Richberg]

Thanks, Bill and Rômulo, for pointing that out. I just checked the
current git version and the problem still remains: If I read, for
example, a .mhd volume image with a spacing not equal to one (not a
DICOM series), write it as DICOM volume file and then read the file, it
will get a z-spacing of 1 (the in-plane spacing, however, is
maintained). If this is really intended, it is kind of an awkward
behavior, imo.

Best regards
Alex

On Thu, 2012-12-06 at 15:52 +0000, Bill Lorensen wrote:
> In ITK 3 and 4 we compute the distance between slice centers (spacing)
> form the image position patient and orientation.
> In ITKv4 there was a bug that was recently fixed. It will appear in
> the 4.3 release. For now, you can try the latest 4.3 release candidate
> which was announced recently on the mailing list.
> 
> On Thu, Dec 6, 2012 at 4:35 AM, Rômulo Pinho
> <romulo.pinho at lyon.unicancer.fr> wrote:
> > Hello, Alex
> > It is indeed a change in GDCM 2.x. You can read about it at
> >
> >
>
http://sourceforge.net/apps/mediawiki/gdcm/index.php?title=Using_GDCM_API#Automatic_ordering_of_slices_for_vtkGDCMImageReader.SetFileNames
> >
> >
>
http://sourceforge.net/apps/mediawiki/gdcm/index.php?title=Imager_Pixel_Spacing#Spacing_along_Z_.28third_dimension.29
> >
> >
>
http://sourceforge.net/apps/mediawiki/gdcm/index.php?title=Using_GDCM_API#Where_is_the_value_of_gdcm.Image.Spacing_coming_from_.3F
> >
> > Kind regards,
> > Rômulo
> >
> >
> >
> > On 12/06/2012 10:16 AM, Alexander Schmidt-Richberg wrote:
> >
> > Hi,
> >
> > sorry if this has been discussed before. I'm sure I'm not the first
to
> > realize, but I couldn't find anything in the mailing lists.
> >
> > I have a problem with reading/writing volume images as Dicom files
> with
> > ITKv4, presumably due to the change from GDCM 1.x to 2.x.
> >
> > In ITK 3, the image spacing was stored in the tags
> > "SpacingBetweenSlices" and "ImagerPixelSpacing". In v4,
> > "NominalScannedPixelSpacing" is used for the in-plane spacing,
> however,
> > the z-spacing is not stored at all (if I'm right). That means, all
of
> > the "old" images I'm reading with ITK4 have a uniform spacing of 1,
> > since the old tags are not interpreted. Moreover, programs like
> MeVisLab
> > ignore the new tag.
> >
> > Has this behavior been discussed? Is it working as intended and is
> there
> > any workaround?
> >
> > Best regards Alex
> >
> >
> >
> > _____________________________________
> > Powered by www.kitware.com
> >
> > Visit other Kitware open-source projects at
> > http://www.kitware.com/opensource/opensource.html
> >
> > Kitware offers ITK Training Courses, for more information visit:
> > http://www.kitware.com/products/protraining.php
> >
> > Please keep messages on-topic and check the ITK FAQ at:
> > http://www.itk.org/Wiki/ITK_FAQ
> >
> > Follow this link to subscribe/unsubscribe:
> > http://www.itk.org/mailman/listinfo/insight-users
> >
>