On 2/18/2021 3:25 PM, Carolina Rimkus wrote:

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I would like to know which are the best ways to normalize the VOI's to intracranial volume.

It is a little controversial right now. Some will simply scale the volume by the eTIV, others will use eTIV as a regressor. I use the first method.

Also, what is the variable BrainSegVol-to-eTIV in aseg? Is it a scaling factor?

This is the ratio of the brain volume as measured by the segmentation to the eTIV. I originally meant it as a QA measure.

Does freesurfer segmentation provide a scaling factor?

The eTIV. If you are running asegstats2table, you can add --etiv and the output table will be the 100000*vol/eTIV (ie, thousands of a percent of eTIV)

Best regards, Carolina

-- Carolina M Rimkus, MD, PhD Neuroradiologist Department of Radiology, Faculty of Medicine, University of São Paulo-SP, Brazil email: carolina.rimkus@usp.br mailto:carolina.rimkus@usp.br carolina.rimkus@gmail.com mailto:carolina.rimkus@gmail.com

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