If you used the Segment button in SPM5, then there will also be a
*_seg_inv_sn.mat file (as well as a *_seg_sn.mat). You can use this to do a
"Write Normalised". If you set the bb to nan(2,3) and the voxel size to
nan(1,3), then the dimensions of the inverse normalised image should be
(about) the same as those of the image from which the parameters were derived
from.
If you didn't use the Segment button, then the Deformations utility of SPM5
can be used for taking a *_sn.mat file, inverting it and writing an inverse
normalised image. The SPM5 manual should give you a few clues.
Best regards,
-John
On Thursday 31 July 2008 16:26, Pierre Gravel wrote:
> Hello
>
>
>
> I have a question about the inversion of the normalisation operation.
>
>
>
> I need to superpose a contrast image (or beta, T, F images), computed in
> normalised space
>
> (T1 MNI), to the original MPrage image of a subject.
>
>
>
> Let us assume that I have MPRage and EPI images
>
> MPrage = 'mprage-Subject.img';
>
> I = 'Subject*.img';
>
>
>
> The realigned images are
>
> rI = 'rSubject*.img';
>
>
>
> The normalised and smoothed images are
>
> wrI = 'swrSubject*.img';
>
>
>
> From those images I compute a contrast image based on a given fMRI model
>
> C = 'con_0006.img';
>
>
>
> How can I invert the normalisation operation to superpose the last result
>
> to the ORIGINAL MPrage image with the same resolution and dimensions?
>
>
>
> I have no trouble going from rI to I using John's Gems #8 but this works
>
> only for solid body transformations. Normalisation is another matter as
>
> it implies a nonlinear transformation.
>
>
>
> Can anyone give me a hand?
>
>
>
> Thanks in advance
>
>
>
> Pierre
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