Anna,
in order to do statistics on the images in native space, they will
(likely) have to be resliced at some point (definitely if you do a
realignment). Reslicing during coregistration may change the resolution
of your functional images to that of the anatomical, which seems to be
what happened to you (if you upsample your functional images to the
anatomical image resolution, this will substantially increase the number
of voxels, and hence, of the time required to perform subsequent steps).
This is not advisable, as you want to keep your original EPI image
resolution. I would probably do realign, or realign and unwarp (which
will reslice anyway) and then do coregister without reslicing, and then
smoothing.
Cheers,
Marko
Anna Blasi wrote:
> Hi All,
>
> I am doing the analysis of my data in native space and I have a question
> regarding pre-processing.
>
> When processing data in native space, when is best to re-slice the
> functional images, at the "Realign" step or at the "Coregister" step? I
> am coregistering the functional data to the space of the structural
> image of each participant. At the end of the coregistration step I
> smooth the data.
>
> I have noticed that the smoothing step and then further processing like
> the 1st level analysis takes a long time to process compared to when I
> did the analysis in Standard Space. If I reslice at the "realign" step,
> then the resolution on the functional results is not great.
>
> My structural scans have very thick slices, probably that does not help.
>
> Many thanks,
>
> Anna
>
--
____________________________________________________
PD Dr. med. Marko Wilke
Facharzt für Kinder- und Jugendmedizin
Leiter, Experimentelle Pädiatrische Neurobildgebung
Universitäts-Kinderklinik
Abt. III (Neuropädiatrie)
Marko Wilke, MD, PhD
Pediatrician
Head, Experimental Pediatric Neuroimaging
University Children's Hospital
Dept. III (Pediatric Neurology)
Hoppe-Seyler-Str. 1
D - 72076 Tübingen, Germany
Tel. +49 7071 29-83416
Fax +49 7071 29-5473
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http://www.medizin.uni-tuebingen.de/kinder/epn/
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