I have three more technical questions on DARTEL that we have used now,
with really improved sensitivity as it seems:
I wondered if for DARTEL also output files of the unified segmentation
(e. g. SPM5) could be used as starting point to start the process?
If I understood it correctly, the import step produces grey matter
segments that only contain the native => affine transformation. Could
this be replaced by native => unified segmentation/cleaning?
(The main reason I ask is rather practical in that the cleaning step
of the unified segmentation was quite helpful to remove misclassified,
and this step is not accessible easily now within DARTEL)
Do images that contain an affine transformation in the header / the nii file
generally need to be resliced before smoothing/testing?
To perform VBM in 1x1x1 resolution, would you recommend to run the whole
template generation at that resolution from scratch? Is reslicing from 1.5
x 1.5 x 1.5
> 1 mm3 introducing a tolerable error (I know, difficult to say; however, I
why the defaults in DARTEL are 1.5 mm and not 1.0 mm as a "typical" VBM
A two-scanner question: for an image pool B with slightly different T1-raw
should we run DARTEL by itself, independently from pool A, and just covary for
it at the stats level? Or would it be okay to warp onto templates of pool A?
Thank you very much in advance for any hints on these questions,
Max Planck Institute of Psychiatry
NMR Research Group
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