Hello Vladimir,
you have actually provided the clue to your problem by faithfully
listing your options, which is highly commendable:
> I did DARTEL estimation of GM volume as it is described in the SPM8
> manual (Chapter 41, Using DARTEL).
> Other approach was using VBM toolbox, as described in “VBM8--‐Toolbox
> Manual” using default settings for writing options (Modulated
> normalized–non linear only).
The "modulated non-linear only" option in the VBM8 toolbox will not do a
"standard" correction for the overall scaling occurring during linear
and non-linear spatial normalization, but will only correct for the
latter. Hence, the scaling resulting from the linear / affine
transformation will not be accounted / corrected for. The average
scaling introduced by the affine procedure in healthy adult brains is
about 1.4, which is likely about the factor that your results differ by.
If you choose the classic modulation in VBM8 (linear & non-linear), then
the results should be closer (if not identical, see some discussions
from the last weeks).
Cheers,
Marko
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____________________________________________________
PD Dr. med. Marko Wilke
Facharzt für Kinder- und Jugendmedizin
Leiter, Experimentelle Pädiatrische Neurobildgebung
Universitäts-Kinderklinik
Abt. III (Neuropädiatrie)
Marko Wilke, MD, PhD
Pediatrician
Head, Experimental Pediatric Neuroimaging
University Children's Hospital
Dept. III (Pediatric Neurology)
Hoppe-Seyler-Str. 1
D - 72076 Tübingen, Germany
Tel. +49 7071 29-83416
Fax +49 7071 29-5473
[log in to unmask]
http://www.medizin.uni-tuebingen.de/kinder/epn/
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