Hi, there,
>From FS Wiki, eTIV - estimated Total Intracranial Volume, aka ICV,
I read
mri_label_volume requires specifying the transform file to use, and the scale
factor: mri_label_volume -eTIV \
$sdir/transforms/talairach.xfm 1948 \
$sdir/aseg.mgz 17 53where $sdir is the path to the subject's mri directory
(ie, $SUBJECTS_DIR/<subjid>/mri). The
'17' and '53' are label ID's, in this case left and right hippocampus
(see the subjects /stats/aseg.stats file for IDs). The output will look
like: using eTIV from atlas transform of 1528 cm^3
processing label 17...
3822 voxels (3822.0 mm^3) in label 17, %0.250119 of eTIV volume (1528075)
processing label 53...
4410 voxels (4410.0 mm^3) in label 53, %0.288598 of eTIV volume (1528075)>From
a previous post at FS mailing list, I also read something similar,
Just as an aside, once you have a talairach_with_skull.lta file (whether
from v3 or v4), you can calculate eTIV as scale_factor/determinant(lta),
where the scale_factor employed is 2150.
Just want to know where dose this scale factor number 1948 and 2150 come from?
Thanks a lot!
Guang
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