Hi,
One way is:
fslmerge -t controls4D <then the list of controls>
fslmaths controls4D -Tstd controls_std
Cheers.
On 1 Feb 2008, at 09:09, Joyce! wrote:
> Thank you all for your suggestions!
>
> I am trying to make a z-value map.
> z = ((FA_map_patient - mean_FA_map_controls)/(sd_FA_map_controls))
>
> So far I made the mean_FA_map_controls using fslmaths:
> fslmaths FS_ctr1 -add FA_ctr2 -add FA_ctr3 -div 3 mean_FA_controls
> (I am using the _FAi_to_target_nonlinear_hr data obtained through
> tbss. I am
> using only 3 controls just to try. )
>
> However, I didn't find the way to make the sd_FA_map_controls... can
> someone
> give me a hint?
>
>
> thank you!
>
>
> Joyce!
>
>
> On Wed, 30 Jan 2008 09:51:39 +0100, Juergen Haenggi
> <[log in to unmask]> wrote:
>
>> Hi Joyce
>>
>> The most appropriate statistical method is a z-value
>> transformation. I
>> recommend to produce a mean and sd image from your control subjects
>> and the
>> compute voxel-wise z-values by z = ((FA map patient - mean FA map
>> controls)/(sd FA map controls)). Then you can threshold this map.
>>
>> Best regards
>> Juergen
>>
>> PS: I would not restrict the FA values only on the skeleton
>> produced by
>> TBSS. Instead leave the TBSS stream after tbss_3_postreg and
>> analyze the
>> whole brain, i.e. All FA values > 2000.
>>
>> Regards
>> Juergen
>>
>>
>> On 30.1.2008 8:59 Uhr, "[log in to unmask]" <[log in to unmask]> wrote:
>>
>>> Hi all,
>>>
>>> I have one patient (n=1) and would like to compare his FA with
>>> a group of controls (n=5).
>>> I have been through all tbss steps as described in
>>> http://www.fmrib.ox.ac.uk/fsl/tbss/index.html (using the
>>> template FMRIB58 for corregistration).
>>> I am now ready to run the statistics but I am not sure about
>>> which procedure is the correct one. My problem is that I am
>>> trying to compare 1 patient with a whole group.
>>> Does anyone know which test can give me a map of FA differences
>>> between the patient and controls?
>>>
>>> I thank you in advance,
>>>
>>> Peace,
>>> Joyce!
>>
>>
>> -----------------------------------------------------------
>> Juergen Haenggi
>> Ph.D. (Dr. des.)
>> Division of Neuropsychology
>> Institute of Psychology
>> University of Zurich
>> Binzmuehlestrasse 14, PO Box 25
>> 8050 Zurich, Switzerland
>> 0041 44 635 73 97 (phone office)
>> 0041 76 445 86 84 (phone mobile)
>> 0041 44 635 74 09 (fax office)
>> BIN 4.D.04 (office room number)
>> [log in to unmask] (email)
>> http://www.psychologie.uzh.ch/neuropsy/ (website)
>> http://www.juergenhaenggi.ch (private website)
>> -----------------------------------------------------------
>> =
>> =
>> =
>> =
>> =====================================================================
>
---------------------------------------------------------------------------
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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