It is hard to say. As Anderson said, we have the improved method for
computing volume. But just because something is improved does not mean
that results will be more significant!
On 5/2/17 1:17 PM, John Anderson wrote:
Dear Doug,
Thank you very much for the clarification!! I highly
Dear Doug,
Thank you very much for the clarification!! I highly appreciate your science
and help.
I received an answer about my question from your colleague Dr Anderson Winkler
(Below) who directed me to review the paper (link also bellow).
My last question is: can Freesurfer 6 address
By noise, I just mean variability, which could come from those sources,
but more likely come from intersubject variability. No good way to check
those. It is looking like volume analysis has much higher false positive
rates than thickness too.
On 5/2/17 12:29 PM, John Anderson wrote:
Thank
Thank you Doug,
One more question please.
Noise: does this mean low quality /high quality T1 images regarding SNR and
contrast between white and gray matter.
What is the correct approach to check noise effect on the reconstructed T1
images to avoid these controversies between cortical and
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
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
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.
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
