Hi,
On 28 May 2007, at 09:27, Benny Liberg wrote:
> Dear FSLers,
>
> I have two questions, and I would really appreciate if anyone could
> help me
> out on this rather simple matter.
>
> I compare 5 individuals that have done two slightly different
> experiments.
> So far, I've done a FFX higher level, regional analysis of both
> experiments. I rerun the higher level analysis with each of the eight
> masks. I then extract the peak vxl from rendered_zstats (avwstats)
> and then
> create a mask containing peak vxl and the 26 surrounding ones
> (avwmaths). I
> then run featquery with that new mask to get mean BOLD % change.
Fine - though it is dangerous to use rended_zstats images - they are
combined greyscale/colourmap images showing activation combined with
a background image. You should use thresh_zstat images
> I can't help thinking that this could be solved by running avwstats
> -x with
> some kind of mask option and then create the 27 vxl ROI with
> avwmaths. Any
> suggestions?
Indeed - see below
> Also, is there any way of dilating a mask?
Sure - use the -dil option in avwmaths.
Steve.
>
> Best regards,
> Benny Liberg
>
>
>
>
> Instead of rerunning the higher analysis with new pre-thr masks
> applied
> masks (8) for each anatomical strucuture, I would like to:
>
> 1. extract the peak vxl within a mask (avwstats) and
> 2. create a new mask containing 26 vxls around the peak vxl
> (avwmaths) and
> extract mean %BOLD change from these 27 vxls.
>
> I know how to do 1 and 2 but can't figure out how to avoid
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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