Hi Stephane,
> I am working on a MRI dataset (females and males aged 9-18 years)
> that has been collected on 6 different scanners (all 3T). My question
> is: in addition to age and gender, I was wondering if I should add an
> additional covariate for scanning site when I create the customized
> tissue probability maps using TOM. Would you also recommend creating
> a covariate for handedness?
This is an interesting question. Generally speaking, if you believe that
"site" explains a substantial portion of the variance, then you could
well argue in favor of including it as a covariate.
The effects of handedness, on the other hand, are not that easily
captured in vbm-type studies so I don't think it will be necessary (we
also looked into this in the 2008 TOM paper and found it not to explain
a substantial part of the variance).
Let me know if this helps,
best,
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
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http://www.medizin.uni-tuebingen.de/kinder/epn/
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