[Insight-users] question on using WarpImageFilter

[John Drozd]

Hi,

I fixed a grammatical error in red my email.  Sorry about my grammatical
blunder.

thank you,
John

On Fri, Jul 29, 2011 at 8:42 AM, John Drozd <john.drozd at gmail.com> wrote:

> Hi,
>
> I and my colleague are using Tom's diffeomorphic demons finite
> difference algorithm (that I found on the Insight Journal) to warp a nifti
> MRI ADNI image1 (what I cll my atlas) to another nifti MRI ADNI image2 (what
> I call my subject).  Both images have float pixel types.  I am using 5
> levels of 15 iterations each with a sigma of 0.8.  I notice that when the
> range between the minimum Jacobian and maximum Jacobian is smaller, the
> warping is more accurate.
>
> I first affine register the atlas to the subject and get a .tfm transform
> file.
>
> I input this .tfm transform file into the diffeomorphic demons code and
> warp the atlas to the subject.
> This generates a deformation field which I use to warp the atlas grey scale
> image to the subject grey scale image.  The warped atlas looks identical to
> the subject.
>
> My atlas has a manually traced hippocampus, and so does my subject.  These
> manual tracings were done by an anatomist.
>
> When I warp the atlas's label map of the hippocampus to the subject, thewarped hippocampus label map does not match the traced hippocampus of the
> subject.  One side looks close but the other side is off, as if the the
> warped hippocampus was twisted.  We find that it is more accurate when an
> interpolator is not used on warping the label map, and when an interpolator
> is used when warping the grey scale image.  Am I and my colleague doing
> something wrong?
>
> Thank you for your time.
>
> John
>
> --
> John Drozd
> Post-Doctoral Fellow, Robarts Research Institute
> The University of Western Ontario
> London, ON, Canada
> http://publish.uwo.ca/~jdrozd2/index.htm
>
>
>


-- 
John Drozd
Post-Doctoral Fellow, Robarts Research Institute
The University of Western Ontario
London, ON, Canada
http://publish.uwo.ca/~jdrozd2/index.htm
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20110729/cae77d2c/attachment.htm>