Dear SPM-experts,
I am analyzing a FDG-PET study (patients before (T1) and after treatment
(T2) and controls at T1 and T2) with SPM2. For the baseline comparison, we
found four clusters which are significant corrected on the cluster level
(at P<0.01 uncorrected). After treatment there are no significant
differences anymore. Now I performed an interaction analyses between
session (T1 vs. T2) and group (patients vs. controls). I want to address
the question which voxels showed a significant change with treatment and
restrict my search volume for whole brain correction to the voxels which
showed a significant difference between patients and controls at T1
(P<0.01 uncorrected).
My question is:
Is it legitimate to create a mask from my baseline contrast (controls >
patients) and use this distributed set of voxels as my search volume in
small volume correction?
Thank you for help and advice! Sorry, if this may be to obvious to experts
on this list.
Best, Florian
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Dr. Florian Schlagenhauf, MD
Department of Psychiatry and Psychotherapy
Charité - Universitaetsmedizin Berlin
Schumannstr. 20/22
10117 Berlin
Germany
Phone +49/30/450 517 257
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