On Wed, 12 Oct 2005, KL Chen wrote:
> when I do the DTI analysis, should I do motion correction of all different
> diffusion gradient orientation images befor I process DTI analysis ? Is
> there any SPM tool can do this work ?
Motion correction of all DW images will be difficult for a number of
reasons
- poor SNR in DW images at high b values
- images with different DW directions have different spatial intensity
patterns (thats why we want to measure DTI...)
I figured that a more robust solution is to do a b0 image every 10-12
diffusion weighted scans (in a 60 directions sequence you would then have
5 or 6 extra b0 images) and do realignment on these images.
My diffusion toolbox (available from the SPM extensions web site) brings a
realignment routine which uses SPM for b0 realignment and then applies the
estimated movement parameters to the DW images measured in between two b0
scans.
Hope this helps,
--
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
|