First of all, make sure that you have all the updates installed. The
"reshape" bug in Matlab 6.5 has a workaround included in the patches. This
bug caused problems in the spatial normalisation of SPM2.
It may be worth looking at the templates to make sure that they have not been
corrupted for some reason.
Ensure that the images you estimate the warps from (source images) have not
been resliced in any way. One of the commonest causes of problems is to do
with the source images being previously resliced.
Further diagnosis of the problem could be made by trying affine spatial
normalisation only. If this goes wrong, then it narrows down the possible
causes.
Other things to check are that the images are oriented roughly the same as the
templates. If the source image spatially normalised OK, and the other images
do not, then make sure that the original data are properly coregistered
beforehand.
That's about it for now,
-John
> I am having a situation in which our functional images appear to be getting
> deformed in the normalization process using SPM2 (but not SPM99). We have
> collected coronal images in which the frontal and occipital regions are not
> fully covered. The raw images look fine, but during the normalization
> stage, it appears that for some (but not all) subjects, the images become
> very distorted. For example, it appears that the brainstem is coming up
> out of the lower left quadrant on the coronal view, and the image in the
> axial view is barely recognizable and appears to be tilted. When we take
> that same subject and normalize the data in SPM99, all the images look fine
> and there are no apparent problems with the data. Has anyone else run
> into this issue or have any idea for a fix in terms of processing out data
> in SPM2? What might cause there to be such a difference in normalization
> of images between SPM99 and SPM2 and why does this "deformation" only
> happen for some subjects in SPM2 but not all?
>
> Any information/advice would be greatly appreciated!
>
> Thank you.
> Eve
>
>
> Eve M. Valera, Ph.D.
> Department of Psychiatry
> Instructor, Harvard Medical School
> Assistant in Research, Massachusetts General Hospital
> 617-724-0307 (office)
> 617-726-4078 (fax)
>
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