Dear Jie Yu,
> I just want to do ( AAL ROI mask ) * ( SPM8 VBM output images )
> I try to do that in fsl
> But there is an error message:
> " attempted to multiply images of different sizes "
>
> But I think they are ALL normalised to MNI space ???
> Is there any way to do this?
Even if images are all normalized to the same space (such as MNI) they
may still have different voxel sizes, etc. The easiest way to take
care of this in SPM is to use the "reslice" function, which will
rewrite new copies of one or more images to match a specified target
image.
So, for example, if you want to have your structural (VBM) images
match the an ROI mask:
1) Go to coregister > reslice only
2) Pick one of your images for the "image defining space". Let's pick
the SPM/VBM image for that.
3) Images to reslice would then be your ROI image(s).
4) Interpolation: If you have a binary ROI and want to keep it binary,
you probably want to pick "nearest neighbor" here. In other cases you
would probably want trilinear or one of the b-spline interpolation
options.
After running this, you should have a resliced ROI image that has the
same size voxels and orientation as your SPM/VBM image, and you should
be able to multiple these in either ImCalc or FSL.
Hope this helps!
Best regards,
Jonathan
--
Jonathan Peelle, PhD
Assistant Professor of Otolaryngology
Washington University in St. Louis
Office: (314) 362-9044
http://peellelab.org || http://jonathanpeelle.net
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