Hi - yes, sorry, if there are no voxels above the threshold then the
co-ordinates reported are meaningless - we'll get that fixed in the
next release.
Cheers.
On 4 Apr 2007, at 00:24, Sang Lee wrote:
> Hi Steve,
>
> The mask image was set to the standard space reference image used
> in the registrations, and the mm coordinates were in the space of
> this image. Also, there were no registration failure nor that the
> voxel that I specified was outside the field-of-view-of the datasets.
>
> Possible that this error is generated when there is no real
> activation in the voxel that I soecified? Looking at each
> individuals that had these errors, all of them did not have any
> activations in the specified voxel. i.e. no activation in the voxel
> is generating these errors. If so, for these individuals, would it
> be ok to assume that the mean % signal change is zero (for the %
> signal change plot)?
>
> Thank you again for your help.
>
> From Sang
> Sang Lee
> Phenotype Genotype Project
> Athinoula Martinos Center for
> Biomedical Imaging
> 149 13th St. Rm. 2302
> Charlestown, MA 02129
> Fax: 617-726-1351
>
>
> On Apr 1, 2007, at 5:29 AM, Steve Smith wrote:
>
>> Hi - did you make sure that the mask image was set to the standard
>> space reference image used in your registrations, and that the mm
>> co-ordinates were in the space of this image? Also, is it possible
>> that the registration had failed for the problematic FEAT runs, or
>> that the voxel you specified was outside the field-of-view of
>> those datasets?
>>
>> Cheers, Steve.
>>
>>
>> On 31 Mar 2007, at 21:37, Sang Lee wrote:
>>
>>> Dear FSL user,
>>>
>>> I am using PE files to calculate the percentage signal change via
>>> featquery for a single voxel for
>>> each of my subjects (total n = 28).
>>>
>>> Given that I am using PE file, an anatomical mask, and a mm
>>> coordinate for a single voxel, using
>>> featquery tool with convert PE/COPE to % signal change option
>>> turned on, I should get % signal
>>> change for each of my subjects for that single voxel.
>>>
>>> However, several of the subjects report file comes out with a
>>> coordinate that I did not specify.
>>>
>>> For example, I specified (-16 -4 -16) for my mm coordinates.
>>> However, several of my subjects'
>>> report file comes out with % signal change values with the
>>> following coordinate (90 -126 -72).
>>> This happens with one third of my subjects. Is there something
>>> that I am doing wrong? How do I
>>> deal with those results with the coordinates that I did not specify?
>>>
>>> I am trying to plot mean % signal change plot for all 28
>>> subjects, but I am not sure what to do with
>>> those subejct's mean % signal change that comes out with a
>>> coordinate that I did not specify.
>>>
>>> Any input would be a great help!
>>>
>>> Thank you in advance.
>>>
>>> From Sang
>>
>>
>> ---------------------------------------------------------------------
>> ------
>> 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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---
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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