Thanks Rosalia!

 

But I am still confused. The IFG ROI was defined from aal templete, which was in MNI space. How can I "make the mask of this region on native, structural image"? Do you mean warp the ROI into native space? then why should normalize back to MNI space?

Also, what does numbers mean in VBM a modulated images, the volume of a voxel? So I only sum up the numbers of voxels within the ROI or do I need to times it with 8 (2mm *2mm*2mm voxel size), or some other calculation?

 

Thanks for the help!

 

2013-05-10

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Chunhui Chen

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State Key Laboratory of Cognitive Neuroscience and Learning

Beijing Normal University

Beijing, China 100875

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发件人： Rosalia Dacosta Aguayo

发送时间： 2013-05-10  13:04:19

收件人： FSL

抄送：

主题： Re: [FSL] How to calculate Region volume on VBM results?

Hi Chenchui,

It would be better to make the mask of this region on native, structural image for every subject. Then, normalize the image and the mask into MNI space and binarize and threshold the mask. Finally, you can calculate the volume with fslmeants.

I hope this helps,
Best
Rosalia.

El 10/05/2013 03:30, "chenchunhuichina" <[log in to unmask]> escribió:

Hello FSLers,

 

I was using FSL-VBM for structural data analysis and it runs smoothly at voxel level. However, I want to calcualte the volume of a region, say IFG, how can I do that? should I do it in native space or in normalized space?

I am not quite sure what the numbers mean for each voxel, can I sum voxels up to get total volume of a region?

 

Thanks for any help!

 

2013-05-09

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Chunhui Chen

_________________

 

State Key Laboratory of Cognitive Neuroscience and Learning

Beijing Normal University

Beijing, China 100875