[Insight-developers] gdcmIO eCT z-spacing patch

[Henning Meyer]

oh oh...
I just figured out, that all the error only happens only with some
special Dicom files I have here. But not with others of the same
scanner.
And it seems the files causing the error are not really valid eCT-Dicom-Files.
For valid files ComputeZSpacingFromIPP works as expected.
Sorry for causing this confusion.

The only thing that still confuses me is the double definition of the
ZTolerance....

Henning

2010/3/22 Mathieu Malaterre <mathieu.malaterre at gmail.com>:
> Henning,
>
> On Mon, Mar 22, 2010 at 4:20 PM, Henning Meyer <tutmann at gmail.com> wrote:
>> Hello All,
>>
>> I encountered problems with handling Toshiba eCT via gdcmIO, due to
>> failure in reading z-spacing.
>> I wrote a patch for InsightToolkit-3.16.0 which works for me.
>> Its basically looking for ImagePositionPatient-Tags inside the
>> PerFrameFunctionalSequence and also checking that the spacing is
>> continuous.
>>
>> I'm still unsure whether or not it's ITKs fault. Because there also
>> seems to be some code doing something similar in gdcm:
>>
>> ./Source/MediaStorageAndFileFormat/gdcmImageHelper.cxx : 159
>> bool ComputeZSpacingFromIPP(const DataSet &ds, double &zspacing)
>>
>> ./Source/MediaStorageAndFileFormat/gdcmIPPSorter.cxx
>
> Neat ! You are using GDCM 2.x :)
>
>> Even though these two seems to be a bit redundant as well (double and
>> different definition of ZTolerance: gdcmImageHelper.cxx:246, and
>> dcmIPPSorter.cxx:30).
>>
>> I'd be happy if we could work this out and patch the right package.
>> Maybe I should repost this in the gdcm-list as well....
>
> I am hijacking this thread to gdcm-dev...
>
> Could you confirm that gdcminfo is failing to report the proper
> z-spacing on your Enhanced CT/MR Image Storage file ?
>
> If so, we have a couple of pathway:
> - Either send me the dataset
> - Send me the output of gdcmdump (at least the Per Frame SQ section).
>
> Thanks !
> --
> Mathieu
>