Fernanda Palhano wrote:
Hello,
I have two questions about volumetric analysis: First: Are the volume measures in the files aseg.stats or ?h.aparc.stats (Gray Matter Volume) already normalized by ICV? Or should I divide all the structure volumes which I want to compare between subjects by the ICV of each subject?
You will need to do the normalization yourself.
Second: When comparing gray matter volumes the correct is use the ICV or the total cortical gray matter volume to normalize? And if I have to use the total cortical gray matter volume, how can I obtain it? I know that this information is in the aseg.stats file, but I was wondering if I can use asegstats2table to extract it.
Whether you should use ICV or GM volume is a matter of debate that depends on exactly what you are trying to do and what structure you are studying. Your hypothesis that you are testing should have a statement about normalization. The ICV and total GM volume automatically show up as a column when you run asegstats2table.
doug
Thank you very much,
Fernanda
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