Dear FreeSurfer team, I'm intrested in the segmentation of Corpus Callosum and in the volumes of its subregions. Freesurfer divides the Corpus Callosum in 5 subregions but I have noticed an inconsistency in the boundary that separates the anterior part from the middle anterior one. In particular, the Rostrum is sometimes included in the anterior part, but other times it is included in the middle anterior part, as you can see comparing the two screenshots that I've attached. How much can I consider this parcellation to be reliable? Thank you, Alessia Giuliano
Hi Alessia
it's tought to tell from a single slice as the subject's head orientation might be a bit slanted. The subregions in the CC are defined purely by the distance along the CC's eigenaxis.
cheers Bruce
On Mon, 26 May 2014, Alessia Giuliano wrote:
Dear FreeSurfer team,
I'm intrested in the segmentation of Corpus Callosum and in the volumes of its subregions.
Freesurfer divides the Corpus Callosum in 5 subregions but I have noticed an inconsistency in the boundary that separates the anterior part from the middle anterior one. In particular, the Rostrum is sometimes included in the anterior part, but other times it is included in the middle anterior part, as you can see comparing the two screenshots that I've attached.
How much can I consider this parcellation to be reliable?
Thank you,
Alessia Giuliano
Dear FreeSurfer team, in order to verify that the segmentation of Corpus Callosum was independent from the initial orientation of the subject MR scan I repeated the recon-all of FreeSurfer in two conditions: 1- when the initial alignement of the scan to the MNI space was gross;2- when the initial alignement of the scan was more precise, but amyway performed manuallly. We found two different results in the CC segmentation and in the resulting volumes of its subregions comparing 1 and 2. How is it possible? I thought that the CC segmentation was performed in the MNI space or with respect to CC eigen axes, but independently from the initial orientation of the scan. Thank you, Alessia Giuliano
Date: Mon, 26 May 2014 12:02:26 -0400 From: fischl@nmr.mgh.harvard.edu To: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Corpus Callosum segmentation
Hi Alessia
it's tought to tell from a single slice as the subject's head orientation might be a bit slanted. The subregions in the CC are defined purely by the distance along the CC's eigenaxis.
cheers Bruce
On Mon, 26 May 2014, Alessia Giuliano wrote:
Dear FreeSurfer team,
I'm intrested in the segmentation of Corpus Callosum and in the volumes of its subregions.
Freesurfer divides the Corpus Callosum in 5 subregions but I have noticed an inconsistency in the boundary that separates the anterior part from the middle anterior one. In particular, the Rostrum is sometimes included in the anterior part, but other times it is included in the middle anterior part, as you can see comparing the two screenshots that I've attached.
How much can I consider this parcellation to be reliable?
Thank you,
Alessia Giuliano
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Hi Alessia
if the talairach is really incorrect that can mess things up. I suspect it's not just the CC, but the aseg as a whole that doesn't look good since we do use the talairach.xfm for some initializations if it is present.
cheers Bruce
On Wed, 28 May 2014, Alessia Giuliano wrote:
Dear FreeSurfer team, in order to verify that the segmentation of Corpus Callosum was independent from the initial orientation of the subject MR scan I repeated the recon-all of FreeSurfer in two conditions:
1- when the initial alignement of the scan to the MNI space was gross; 2- when the initial alignement of the scan was more precise, but amyway performed manuallly.
We found two different results in the CC segmentation and in the resulting volumes of its subregions comparing 1 and 2.
How is it possible? I thought that the CC segmentation was performed in the MNI space or with respect to CC eigen axes, but independently from the initial orientation of the scan.
Thank you,
Alessia Giuliano
Date: Mon, 26 May 2014 12:02:26 -0400 From: fischl@nmr.mgh.harvard.edu To: freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Corpus Callosum segmentation
Hi Alessia
it's tought to tell from a single slice as the subject's head orientation might be a bit slanted. The subregions in the CC are defined purely by the distance along the CC's eigenaxis.
cheers Bruce
On Mon, 26 May 2014, Alessia Giuliano wrote:
Dear FreeSurfer team,
I'm intrested in the segmentation of Corpus Callosum and in the volumes of its subregions.
Freesurfer divides the Corpus Callosum in 5 subregions but I have noticed
an
inconsistency in the boundary that separates the anterior part from the middle anterior one. In particular, the Rostrum is sometimes included in the anterior part, but other times it is included in the middle anterior part, as you can see comparing the two screenshots that I've attached.
How much can I consider this parcellation to be reliable?
Thank you,
Alessia Giuliano
_______________________________________________ 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@nmr.mgh.harvard.edu
-
Alessia Giuliano -
Bruce Fischl