Dear Dr Doug, I followed wiki to adjust the volumetirc measures to eTIV usign the command
mri_label_volume -eTIV \ $sdir/transforms/talairach.xfm 1948 \ $sdir/aseg.mgz 17 53
Kindly, 1. What is the saling factor stands for and why it is specifically "1948 " is this only relevant to volumetrics? if so what is the scaling factor for surfaces? 2. I am wondering if there is any command to adjust surface area to eTIV similar to the command "mri_label_volume", and how to do this adjustment so I highly appreciate any ideas?
Thanks John
-----Original Message----- From: freesurfer-bounces@nmr.mgh.harvard.edu [mailto:freesurfer-bounces@nmr.mgh.harvard.edu] On Behalf Of Douglas N Greve Sent: Monday, May 8, 2017 5:55 PM To: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Surface area
Yes, I would recommend making some kind of adjustment. As with all such adjustments, the adjustment you choose will dictate how you interpret the results (eg, a eTIV adjustment means something different that an adjustment for whole brain volume). For surface area, I usually adjust the eTIV. It might seem strange to adjust surface area by a volume, but for a highly folded surface, the surface area actually goes up linearly with the volume. But adjusting by total surface area is ok too.
On 05/08/2017 02:29 PM, John Anderson wrote:
Dear Freesurfer experts,
I know that the grey or white matter volume measures for the ROIs
reported in "wmparc.mgz" can be adjusted for the total intracranial
volume.... Is is correct to do the same for surfaces? I mean can the
surface of an ROI (e.g. precentral) be adjusted to total surface area?
If yes, this must be done for total white right or total left
depending on the ROI if it is left or right, correct?
Thank you
John
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