Dear Naoki,
using atlases such as pickatlas is of some help by relating your results to pre-defined regions. However, you have to keep in mind that the regions are always linked to a certain template or space. If you use DARTEL or any other high-dimensional spatial registration there will be always discrepancies between the anatomical spaces. Even if the VBM8 DARTEL template is in MNI space, there are of course local deviations because the registration approaches and templates differ. Thus, the automatical identification of regions might be just a first guess and I always recommend to use your averaged normalized T1 images for a final decision about the underlying region.
Best,
Christian
On Sat, 11 Jan 2014 17:06:20 +0900, 平林 直樹 <[log in to unmask]> wrote:
>Dear Christian,
>
>thank you very much for your reply.
>
>If I create my own DARTEL template in VBM8, is it difficult to identify the brain region by using pickatlas?
>Or a customized DARTEL template is also registered to MNI space(?), so can I identify the brain region by using pickatlas?
>
>Like SPM8, if I create my own DARTEL template in VBM8, is images registered with MNI space using only affine registration?
>Thanks for your help.
>
>Best,
>Naoki
>
>--- On Wed, 2014/1/8, Christian Gaser <[log in to unmask]> wrote:
>
>
>
>Dear Naoki,
>
>for elderly subjects or even Alzheimer's patients I only use the standard DARTEL template that is used by VBM8. Only for children data I create a customized template. However, this is purely based on my personal experience and if you have a large, representative sample of elderlies you will make nothing wrong by creating your own DARTEL template.
>
>You can create this template with the DARTEL toolbox by using the segmentations either from SPM12b or VBM8. I would strongly recommend to use rather the segmentation of SPM12b than SPM8 because there is a large improvement in segmentation quality especially for subjects that deviate from healthy control subjects. In VBM8 you can also export the segmentations to DARTEL via the option "DARTEL export| affine".
>
>Best,
>
>Christian
>
>On Tue, 7 Jan 2014 10:22:48 +0000, Naoki Hirabayashi <[log in to unmask]> wrote:
>
>>Dear Experts,
>>
>>I'd like to know which algorithm is suitable for voxel based morphometry of the elderly, SPM8 or VBM8 algorithm?
>>
>>In my understanding an already existing Dartel template in MNI space is used in VBM8 procedure.
>>
>>In SPM8 procedure, dartel template which is created from all subjects is used.
>>
>>
>>Any suggestion would be highly appreciated.
>>
>>
>>Thank you so much,
>>Naoki Hirabayashi
>
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