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
_________________________________________________________________ Hotmail: Free, trusted and rich email service. http://clk.atdmt.com/GBL/go/171222984/direct/01/