[vtkusers] How does vtk create volume from dicom CT scans ?

[Mathieu Malaterre]

Salut Nicolas,

On Mon, Oct 19, 2009 at 10:40 AM, Gerber, Nicolas
<nicolas.gerber at istb.unibe.ch> wrote:
> Dear all,
>
>
>
> I was wondering how do you do internally to create a volume from a stack of
> CT scans or any other dicom modality ?
>
>
>
> Especially, how do you treat these issues:
>
> -          The slice thickness varies among the stack.
>
> -          The slice orientation varies among the stack.
>
> -          We cannot rely on the dicom tags for the slice thickness.
>
>
>
> If the slice thickness is not constant among the stack, do you get the hole
> volume and re-slice it (it then involves interpolation) ?

This is mostly described here:
http://sourceforge.net/apps/mediawiki/gdcm/index.php?title=Using_GDCM_API#Automatic_ordering_of_slices_for_vtkGDCMImageReader.SetFileNames

I believe you are talking about the old MR/CT Image Storage, in this
case whenever the Slice thickness is changing or the slice Orientation
is changing you have a different Series UID. Therefore you'll be able
to sort the Series based on that DICOM attribute (see gdcm::Sorter
class).
Ref:
http://gdcm.sourceforge.net/html/classgdcm_1_1Sorter.html


If you are talking about the new Enhanced MR/CT Image Storage... then
you are screwed :) I did not implement this case, but I would really
like to see those kind of files !

Cheers
-- 
Mathieu