Dear experts,
we are using SPM5 to compare patients vs. controls with fMRI. Our patients
do not have gross anatomical abnormalities (this is one of the exclusion
criteria). Yet, since the mean-age of both patients and controls is about 43
± 8 (a little bit elder than the volunteers from which the MNI template was
created) we are wondering whether we should use a specific template for
normalization, and we are trying to distinguish among 3 options:
1) to run the classical pre-processing and simply taking the deformation
parameters for normalization from the segmentation of the individual T1
images (coregistered to the mean of the realigned functional images). In
this case, one further option would be to use the "no priors" option of the
VBM-toolbox 5.1
2) to search for an age-specific template. Provided that such templates do
exist/are available somewhere, probably this would be the option for the
best normalization as possible, yet the results would not be in the MNI
space, and thus they could not be directly compared with those from other
studies. Therefore, I would be inclined to discard this option.
3) to create an ad-hoc-template, but since we don't have hundreds of images
(just 15 patients and 15 controls) this does not sound feasible
Any suggestions/criticism about these options?
Many thanks in advance,
best wishes,
nicola
***************************
Nicola Canessa, Ph.D.
CRESA, www.cresa.eu
San Raffaele Research Institute,
Via Olgettina 58,
20132, Milano, Italy
+39-02-2643-4888
[log in to unmask]
***************************
|