Dear Chris,
> for the analysis of SPECT perfusion data, I would like to "crop" my images
> prior to statistical analysis
> - that is, remove non-brain counts [scalp, sinuses, muscles]
>
> from reading about "Mask object" in spm_sn3d, I gather spm will not do this
> during this step. True?
>
> if not, is there a function available to do so?
Yes, there is a function to do exactly what you want. During the
statistical analysis set-up, you can specify an explicit masking. To get
to this and related masking options, you have to choose Full Monty as
your design option. Then you can specify a mask-image, which could be in
your case e.g. a normalized cropped image, where NaN (or 0) would mean
to exclude this voxel from the analysis. You find a more detailed
documentation about this type of masking in the SPM-help for PET-models.
Stefan
--
Stefan Kiebel
Functional Imaging Laboratory
Wellcome Dept. of Cognitive Neurology
12 Queen Square
WC1N 3BG London, UK
Tel.: +44-(0)20-7833-7478
FAX : -7813-1420
email: [log in to unmask]
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|