Hello
I just wanted to check that when calculating % change maps using the
method below (PE*PP Height/mean_func) for e.g. an off-on-off paradigm, that
the % increase is calculated from the mean of the 'on' time points rather than
the peak signal during the 'on' time points?
If so do you know of anyway to calculate peak signal change maps? In my
pharmacological expt the signal increase in lesion happens slowly over a
minute or so while the but may be increased in magnitude, compared to
the 'normal' hemisphere where the peak signal increase occurs more rapidly
but is of lesser magnitude -I want to bring that out in the images.
Thankyou so much
Krishna
Subject: Re: Whole Brain Percentage Maps
From: Steve Smith <[log in to unmask]>
Reply-To: FSL - FMRIB's Software Library <[log in to unmask]>
Date: Wed, 2 Sep 2009 07:22:46 +0100
Content-Type: text/plain
Parts/Attachments: text/plain (40 lines)
Hi - yes this is easy - e.g. for EV1, if you take the PE1 map .feat/
stats/pe1.nii.gz and multiply by the peak-peak height of EV1 (you can
find this in the header of design.mat) and divide by mean_func you'll
get what you want - this is all easy with fslmaths.
Cheers.
On 2 Sep 2009, at 03:11, Krishna Dani wrote:
> Dear FSL,
>
> I am new to FSL and would like to ask your advice.
>
> I am using a pharmacological stimulus which will likely produce
> different
> changes in lesioned and normal tissue. Therefore I would like to
> produce a
> percentage change map for the whole brain.
>
> Uisng the GUI I have successfully interorrogated FEAT using
> featquery, using a
> whole brain mask. Is it possible to produce a whole brain percentage
> change
> map aswell?
>
> Thankyou
>
> Krishna
>
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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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