Dear Francesca,
you might want to have a look at the methods section of
Sach et al: Diffusion tensor MRI of early upper motor neuron involvement
in amyotrophic lateral sclerosis, Brain (2004), Vol 127 no 2,pp 340-350
DOI: 10.1093/brain/awh041
There we have used T1 images acquired in the same session to determine
normalisation parameters. If your DWI images are EPI, then you could try
normalising the b0-datasets to the EPI template instead. To make sure that
you are comparing FA differences and not other anatomical changes which
result in different location of fiber tracts, you should do a VBM on white
matter - if there are differences in VBM in areas where you would look for
changes in FA, then there is no easy way to determine whether you observe
true changes in FA or only displacement of fiber tracts.
Yours,
Volkmar Glauche
On Fri, 13 Feb 2004, Francesca Caramia wrote:
> Dear SPM users,
> We're planning to use SPM2 to compare FA maps from 20 patients with 20 normal controls and we believe that we should create our own template. We have the following questions:
> 1) Which is the best template? an FA template?
> 2) We should create a template from all subjects (patients and controls?)
> Thank to all
> Francesca
--
Volkmar Glauche
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Department of Neurology E-Mail [log in to unmask]
UKE Hamburg Phone 49(0)40-42803-5781
Martinistr. 52 Fax 49(0)40-42803-9955
20246 Hamburg
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