Hello,
I have a question regarding volume-correction for the morphometry stats obtained via recon-all. I’ve noted that eTIV is derived using the atlas scaling factor in order to account for head size. I’m wondering whether the other volumes given, e.g. TotalGray or lhCorticalWhiteMatter, have also been corrected for head size? If not, is there a recommended method in which to do so so that regional volumes can be compared between participants?
Many thanks for your help!
Best,
Christina
Hi Christina
we don't correct any volumes for head size - we just provide the information for you to do it yourself. I think including it as a regressor is more common than dividing it out, but perhaps others can comment.
cheers Bruce On Mon, 11 Jan 2016, Christina van den Brink wrote:
Hello, I have a question regarding volume-correction for the morphometry stats obtained via recon-all. I’ve noted that eTIV is derived using the atlas scaling factor in order to account for head size. I’m wondering whether the other volumes given, e.g. TotalGray or lhCorticalWhiteMatter, have also been corrected for head size? If not, is there a recommended method in which to do so so that regional volumes can be compared between participants?
Many thanks for your help!
Best,
Christina
Hi Bruce (and the freesurfer community),
Thanks for your reply! Would it be possible to get more details on the process of how I might go about correcting these volumes myself? It would be ideal if I had the volumes prior to entering it into my statistical model (and thus I’d prefer not to use head size as a regressor if possible). When you say ‘dividing it out’, is this simply taking the regional volumes and dividing it by eTIV to obtain a proportion? What are the downsides to approaching it in this manner vs. using it as a regressor?
Many thanks,
Christina
On Jan 11, 2016, at 12:46 PM, Bruce Fischl fischl@nmr.mgh.harvard.edu wrote:
Hi Christina
we don't correct any volumes for head size - we just provide the information for you to do it yourself. I think including it as a regressor is more common than dividing it out, but perhaps others can comment.
cheers Bruce On Mon, 11 Jan 2016, Christina van den Brink wrote:
Hello, I have a question regarding volume-correction for the morphometry stats obtained via recon-all. I’ve noted that eTIV is derived using the atlas scaling factor in order to account for head size. I’m wondering whether the other volumes given, e.g. TotalGray or lhCorticalWhiteMatter, have also been corrected for head size? If not, is there a recommended method in which to do so so that regional volumes can be compared between participants? Many thanks for your help! Best, Christina
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Hi Chistina,
the aseg.stats has all that information. You can create a table from all subjects with asegstats2table . It will also contain the ICV (probably called eTIV or something like that). And you can use it in your model, which is probably the best approach.
Cheers, Martin
On 01/24/2016 02:58 PM, Christina van den Brink wrote:
Hi Bruce (and the freesurfer community),
Thanks for your reply! Would it be possible to get more details on the process of how I might go about correcting these volumes myself? It would be ideal if I had the volumes prior to entering it into my statistical model (and thus I’d prefer not to use head size as a regressor if possible). When you say ‘dividing it out’, is this simply taking the regional volumes and dividing it by eTIV to obtain a proportion? What are the downsides to approaching it in this manner vs. using it as a regressor?
Many thanks,
Christina
On Jan 11, 2016, at 12:46 PM, Bruce Fischl fischl@nmr.mgh.harvard.edu wrote:
Hi Christina
we don't correct any volumes for head size - we just provide the information for you to do it yourself. I think including it as a regressor is more common than dividing it out, but perhaps others can comment.
cheers Bruce On Mon, 11 Jan 2016, Christina van den Brink wrote:
Hello, I have a question regarding volume-correction for the morphometry stats obtained via recon-all. I’ve noted that eTIV is derived using the atlas scaling factor in order to account for head size. I’m wondering whether the other volumes given, e.g. TotalGray or lhCorticalWhiteMatter, have also been corrected for head size? If not, is there a recommended method in which to do so so that regional volumes can be compared between participants? Many thanks for your help! Best, Christina
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
freesurfer@nmr.mgh.harvard.edu
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Bruce Fischl -
Christina van den Brink -
Martin Reuter