You are speaking statistically, I assume? Ie, you see a sig change in
volume and not thickness, or vice versa? If so, it can easily be
explained by differences in noise
On 5/2/17 5:00 AM, John Anderson wrote:
Hi Doug,
Thank you for the detailed explanation!
Please I have one follow-up question and I highly appreciate your input
How can we explain results related to reduce cortical thickness and
normal gray matter volume. Are these parameters two different thing or
they are related to each other.? In other words:
If (cortical thickness = gray matter volume * area ) that means reduce
cortical thickness must be accompanied by reduce gray matter volume
and vice versa.
My question is: Have you seen similar cases for a reduction in
cortical thickness and normal gray matter volume. I f yes how can
this, at least, be explained mathematically.
All the best,
John
The thickness is an average of two numbers. One is the distance from a
white surface vertex to the pial surface along the normal to the
white. The other is the distance from the pial to the white along the
normal to the pial.
Volume (in v6) is computed as the volume of a truncated tetrahedron.
Prior to v6 it was surface area times thickness
-------- Original Message --------
Subject: Volume vs cortical thickness
Local Time: April 10, 2017 12:24 PM
UTC Time: April 10, 2017 4:24 PM
From: john.ande...@protonmail.com
To: freesurfer@nmr.mgh.harvard.edu <freesurfer@nmr.mgh.harvard.edu>
Dear Freesurfer experts,
I highly appreciate if anybody clarify how Freesurfer calculate
cortical thickness and gray matter volume.
If the cortical thickness of e.g. precentral gurus is measured as the
closest distance from the gray-white boundary to the gray-CSF boundray
at each vertex on the tessellated surface (Fischl and Dale. 2000).
How the gray matter volume for the precentral gyrus was measured?
Thank you for any clarification!
John
Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu >
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Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone
Number: 617-724-2358 Fax: 617-726-7422 Bugs:
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