[vtkusers] MRI MPR labelling ( L/R, A/P, S/I).

[prakash kotre]

Dear all,

finally I was able to make the 3D MPR with correct labels. Thanks for the
post
http://vtk.1045678.n5.nabble.com/vtkImageReslice-class-td1233015.html#a1233025

Which explained the conversions as well as the working of vtkImageReslice
filter.

look for below word in that post.
 x = T*M*x' where "T" is ResliceTransform and "M" is ResliceMatrix

My learning:

1) dicom is left hand system and vtk is the Right handed system. To convert
to and from
    create the vtkDataSet in nth image to first image. last image is
inserted at first and first image is inserted last in sequence.
2) Apply above formula to calculate the effective direction cosines for the
arbitrary plane.

Xeffective = Orientation*T*M
where :
             Xeffective : Effective direction cosine.
                        T : Reslice Transform.
                       M : ResliceMatrix of vtkImageReslice class.
                       Orientation : Dicom orientation read from data set.

This gave me the correct labelling with any rotations (oblique,double
oblique).

Once again thank you.

------------------------------------
Prakash.
Learn to share and share to learn.


On Mon, Jan 9, 2012 at 3:26 PM, prakash kotre
<prakash.medsphere at gmail.com>wrote:

> Hi all,
> Any Ideas on this issue?
>
> Thanks and regards
> Prakash
>
>
> On Fri, Dec 30, 2011 at 5:53 PM, prakash <prakash.medsphere at gmail.com>wrote:
>
>> Dear all,
>> I am working on MRI MPR.
>> I am stuck with MR images labelling part.
>> I use dcmtk 3.5.4 ( dicom parsing/reading) and vtk 5.4
>> ( vtkImageReslice algorithm).
>>
>> The directionCosines of the vtkImageReslice  slicer is taken to
>> calculate the side labels.
>>
>> If MRI is acquired in Axially its image orientation is 1,0,0/0,1,0 and
>> the side markers are showing correctly.
>>
>> But If MRI is acquired other than axial then orientation is different.
>> the marker calculations are going wrong.
>>
>> I think, I need to calculate the side markers taking image orientation
>> in consideration.
>>
>> But I dont know how to do it. Could you please help me ?
>>
>> My MPR 3 views are:
>>
>> Transform->Identity();
>> view1 : break.
>> view2 : Transform->RotateX(90);
>> view3 : Transform->RotateY(90);
>>
>> Thanks and regards
>> Prakash
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.vtk.org/pipermail/vtkusers/attachments/20120125/1a78bb51/attachment.htm>