Dear SPMers:
I have 2 questions:
The context of my questions arise from this error:
SPM2: spm_fmri_spm_ui (v2.52) 13:58:28 - 08/04/2004
=======================================================================
Mapping files : ...done
??? Error using ==> spm_fmri_spm_ui
images do not all have same orientation & voxel size
??? Error while evaluating uicontrol Callback.
First question:
---------------
If after having performed a coregister (which creates f*.mat) ) + reslice
(which apply the f*.mat computed earlier to create the rf*.[img, hdr] to
correct for the movement, and THEN did a coregister *only* just to access
the extent of the residual movement (after the correction), i.e. to
appreciate the quality of the corrected images, THEN THE .mat THAT WERE
CREATED BY THIS second coregister (only) SHOULD BE REMOVED, otherwise those
rf*.mat will *corrupt* the subsequent steps of my analysis (which are what
exactly...) where the .mat will be taken into account.
Am I right? (if they were not removed, then the above error could occur)
Second question:
-----------------
I have converted a functional images from DICOM to ANALYSE using the DICOM
toolbox in SPM2 and I noticed the presence of .mat files.
My question is:
Should I get rid of the .mat BEFORE starting an analysis (preprocessing +
model estimation, ...) or can I leave them there?
I checked using display the values for the voxel size, the origin, the
orientation of the images and I compared for example what display tells me
when the .mat is and is not there, i.e.:
image1.hdr
image1.img
image1.mat
in the first case, and,
image1.hdr
image1.img
image1.mat_HIDDEN (renamed so not to be taken into account by display)
in the other case.
So when I compare the voxel size, dimension, origin and orientation when the
.mat is present versus when it is abscent, these parameters are either
exactly the same (for a specific data set) or rounded for the origin when
the .mat is removed using another dataset, as if the .mat doesn't contain
useful information.
What should I conclude regarding the *usefulness* of the .mat for the raw
ANALYSE images (i.e. before not processing was made to them), and should I
get rid of them before starting the analysis.
Thanks
Yves Roy
|