Dear Edward,
if you are using the diffusion toolbox to estimate the tensor, there is
a module called "Copy and reorient diffusion information". It works on
the diffusion weighted images and applies motion
correction/coregistration/affine normalisation parameters to the
gradient directions.
To apply non-linear deformations, you need to run "Warp tensors" after
tensor estimation. This will apply the non-linear part of spatial
normalisation parameters. You should be aware however, that there still
are discussions on the effects of spatial normalisation when applied to
tensors.
If you are interested in rotation-invariant properties of the tensor
(eigenvalues, FA, mean diffusivity...), you don't need to bother about
the normalisation parameters at all.
Volkmar
Am Donnerstag, den 18.12.2008, 16:07 +0800 schrieb Hui, Edward SK:
> Dear SPM experts,
>
>
> I am a rookie in SPM and know very little after the maths behind
> coregistration. Therefore I need your kind help in answering the
> queries that I have below.
>
>
> I work with diffusion tensor image data. After using SPM to do the
> normalization of the raw data (DWI along each diffusion encoding
> direction), it is necessary to also reorient the gradient table.
> Hence, I am wondering how could I use the information from *_sn.mat on
> the gradient table such that the gradient table is reoriented like the
> way the raw DWI data are? Or in other words, which equations/lines of
> codes in SPM can be used to do the job?
>
>
> Many thanks for your kind help and time in advance.
>
>
> Best regards,
> Edward
> ---------------------
> Edward S. Hui
> Ph.D. Candidate
> Dept. of Electrical and Electronic Engineering
> Laboratory of Biomedical Imaging and Signal Processing - 7T MRI Lab
> University of Hong Kong, Pokfulam, Hong Kong
> Tel (LB1002): (+852) 28199712
> Email: [log in to unmask]
> [log in to unmask]
> Website: http://www.hku.hk/bisplab
> ------------------------------------------------------------------------------------------------------
>
>
--
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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