[vtkusers] What ditermines whether the slice order should be reversed?

[David Gobbi]

Hi Rajesh,

With vtk-dicom and the vtkDICOMReader, it is possible to get the value of
any DICOM tag as described here:
http://dgobbi.github.io/vtk-dicom/doc/api/attributes.html

You can use vtk-dicom with any version of VTK from 5.10 through VTK 8.  In
VTK 7 and 8, you just have to set Module_vtkDICOM:BOOL=ON when you
configure VTK with cmake.

The vtkDICOMReader is not to be confused with VTK's built-in
vtkDICOMImageReader, which provides fewer options.

Cheers,
 - David


On Sun, Aug 27, 2017 at 6:10 PM, Ramamurthy, Rajesh (GE Global Research,
US) <ramamurr at research.ge.com> wrote:

> David,
>
>
>
> Another follow-up question. In VTK7.1.1, is there a method to tell  the
> slice location tag? I found other methods e.g. , for slice spacing but not
> slice location. Or is there a function that returns all the tags, and we
> can get the information that way?
>
>
>
> Thanks
>
> Rajesh
>
>
>
> *From:* vtkusers [mailto:vtkusers-bounces at vtk.org] *On Behalf Of *David
> Gobbi
> *Sent:* Sunday, August 27, 2017 3:30 PM
> *To:* Liu_tj
> *Cc:* vtkusers
> *Subject:* EXT: Re: [vtkusers] What ditermines whether the slice order
> should be reversed?
>
>
>
> Hi Liu Peng,
>
>
>
> The vtkDICOMReader sorts according to the Image Plane Module:
>
> http://dicom.nema.org/MEDICAL/dicom/current/output/chtml/par
> t03/sect_C.7.6.2.html
>
> That is, the slices are sorted in a manner such that the VTK image data
> has a right-handed coordinate system (called an RCS in the link above).
>
>
>
> Sorting the slices to get an RCS means that sometimes the slices will be
> sorted the same as the InstanceNumber, and sometimes they will be sorted
> opposite to InstanceNumber, depending on the order in which scanner ordered
> the slices.
>
>
>
> You can perform the sorting yourself by calling reader->SortingOff().  If
> Sorting is Off, the reader will take the slices in the same order as the
> vtkStringArray that you passed to reader->SetFileNames().
>
>
>
> If you send me the block of code where you set up and call the reader,
> then I might be able to provide more help.  Don't forget to also say what
> versions of VTK and vtk-dicom you are using.
>
>
>
> Cheers,
>
>  - David
>
>
>
>
>
>
>
> On Sun, Aug 27, 2017 at 10:41 AM, Liu_tj <tjlp at netease.com> wrote:
>
> Hi,
>
>
>
> I have a question about the DICOM slice order. I use the DICOM reader by
> David Gobbi to read the slice series to vtkImageData. And I found that the
> oder is the same as the order by DICOM instanceNumber tag. However, some
> doctors tell me that the order should be reversed because the scan should
> start from head to foot.
>
>
>
> @David, if I need to reverse, how to achieve that by your DICOM reader?
>
>
>
> Thanks
>
> Liu Peng
>
>
>
>
>
>
>
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