Well, a lot of conversions and changes between different software
suites... Probably you did different processing on some of your scans. SPM
requires that all images which go into stats have same voxel size, image
dimensions and orientation. If you changed (perhaps by accident) the voxel
size or bounding box in normalisation defaults for some of your subjects,
then this may happen. SPM5 has an spm_check_orientation m file, which is
more informative than SPM2.
But what do you want to test on your B0 images anyway?
Volkmar
On Tue, 19 Dec 2006, Suzanna Laycock wrote:
> Hi all,
>
> I'm afraid this may be a very basic question, but I'm trying to analyse some
> DTI data.
>
> The steps I've taken so far are (briefly): scanned 2 groups of people -
> control and experimental group, acquired DTI data from Philips Intera, used
> FSL to convert into Analyze format, eddicorrect and align to SPM
> orientation, DTIStudio to generate and save B0 and FA maps, SPM2 normalise
> the B0 to the EPI template and write the parameters to the FA (and B0) maps,
> SPM2 to smooth the normalised B0 (as recommended by a previous SPM mailing
> list user).
>
> Then comes the problem.
>
> I used a 2 sample T-test in the basic models to compare the smoothed,
> normalised B0 scans between the two groups; I then planned to extrapolate
> the same corrordinates from the FA maps. However, I get an error message in
> Matlab which says:
>
> ??? Error using ==> spm_spm_ui
> images do not all have the same dimensions
>
> Why is this? I thought normalising pit the images into a standard space
> which enabled one to carry out statisticl analysis between two groups. Have
> I missed out an important step in the analysis processes?
>
> All advice gratefully received....sorry if this is a basic problem!
>
> Suzanna
>
>
> ----------------------------------------------------------------
> Miss Suzanna K. Laycock
> Postgraduate Student
> Department of Psychology and Academic Unit of Radiology
> Weston Bank, Sheffield, S10 2TN, UK
> Phone: (0114) 22 26526
> Email: [log in to unmask]
>
>
--
Volkmar Glauche
-
Department of Neurology [log in to unmask]
Universitaetsklinikum Freiburg Phone 49(0)761-270-5331
Breisacher Str. 64 Fax 49(0)761-270-5416
79106 Freiburg http://fbi.uniklinik-freiburg.de/
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