External Email - Use Caution
Hi, I am looking at interscanner differences between Philip and GE. I get significantly less variation between the scanners when looking at sbTIV (coefficient of variation < 1.5 %) than eTIV (12%) within subjects. Any thought as to why? Normalizing ROIs with sbTIV improves these differences even more.
Thanks for your help.
AJ
The two methods are totally different. See https://surfer.nmr.mgh.harvard.edu/fswiki/sbTIV the sb version actually performs a skull segmentation and counts voxels within skull. The eTIV is computed from the talairach registration, which is going to be inherently more variable (eg, more or less neck will affect it).
On 7/20/2021 3:24 PM, AJ wrote:
External Email - Use Caution
Hi, I am looking at interscanner differences between Philip and GE. I get significantly less variation between the scanners when looking at sbTIV (coefficient of variation < 1.5 %) than eTIV (12%) within subjects. Any thought as to why? Normalizing ROIs with sbTIV improves these differences even more.
Thanks for your help.
AJ
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
External Email - Use Caution
Many thanks. Best
On Tue, Jul 20, 2021, 14:36 Douglas N. Greve dgreve@mgh.harvard.edu wrote:
The two methods are totally different. See https://secure-web.cisco.com/1M9K3lSgALVk9H3YxzU4beySwAyD9LUr7aJIifLSz-a7CIw... the sb version actually performs a skull segmentation and counts voxels within skull. The eTIV is computed from the talairach registration, which is going to be inherently more variable (eg, more or less neck will affect it).
On 7/20/2021 3:24 PM, AJ wrote:
External Email - Use CautionHi, I am looking at interscanner differences between Philip and GE. I get significantly less variation between the scanners when looking at sbTIV (coefficient of variation < 1.5 %) than eTIV (12%) within subjects. Any thought as to why? Normalizing ROIs with sbTIV improves these differences even more.
Thanks for your help.
AJ
Freesurfer mailing listFreesurfer@nmr.mgh.harvard.eduhttps://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://secure-web.cisco.com/1DDuQL9Kl6zOIpPWhQAXUSEacQhKZw8Sr9xZB53po8hkAxW... 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 Mass General Brigham Compliance HelpLine at http://secure-web.cisco.com/15fQ02uIVGDHLLoPbHL29Ebc66_OWtqHdmJ8-A9X0uO9wG6f... . 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. Please note that this e-mail is not secure (encrypted). If you do not wish to continue communication over unencrypted e-mail, please notify the sender of this message immediately. Continuing to send or respond to e-mail after receiving this message means you understand and accept this risk and wish to continue to communicate over unencrypted e-mail.
freesurfer@nmr.mgh.harvard.edu
-
AJ -
Douglas N. Greve