That is surface-based smoothing. the voxel size differences create
differences in volume-based smoothing (a partial volume effect). I don't
know of a good way to simulate volume-based PVC. This cannot be done in qdec
On 10/06/2016 06:36 PM, Martin Juneja wrote:
> Dear Dr. Greve,
>
> Thanks a lo
Dear Dr. Greve,
Thanks a lot for your inputs on this.
In the manual-
https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/QdecGroupAnalysis_freeview,
in qdec it shows there is an option to select 'Smoothing (FWHM)' under the
step 'Design'. Could you please share your thoughts if there is any optim
I think the difference in voxel size (1mm vs 1.3mm) is problematic. You
will get more smoothing with the 1.3mm (ie, partial volume effects), and
that could easily show up in the thickness measurements
On 10/05/2016 12:19 PM, Martin Juneja wrote:
> Hi Dr. Greve,
>
> After I compare the two proto
Hi Dr. Greve,
After I compare the two protocols (after using mri_info in FSL on raw dicom
file), I get following parameters used in both the protocols. After looking
at both the protocols parameters below, could you please share your
thoughts on whether parameters are in match enough to go ahead a
I would still say no -- the differences could still be due to
differences in acquisition parameters
On 10/03/2016 02:30 PM, Martin Juneja wrote:
> Thanks Dr. Harms and Dr. Greve.
> So can I do the cortical thickness comparison if we have healthy
> controls data from the same scanner but acquire
Thanks Dr. Harms and Dr. Greve.
So can I do the cortical thickness comparison if we have healthy controls
data from the same scanner but acquired using different protocol e.g. if we
get access of age-matched healthy controls data from another lab who used
the same scanner?
Thanks.
On Fri, Sep 30,
You can do the comparison, but the interpretation is difficult. If you
see a difference, how do you know it is not due to the scanner? There's
not much you can do ...
On 09/29/2016 02:54 PM, Martin Juneja wrote:
> Hello FS experts,
>
> I have a data set of 20 subjects (patients) collected at lo
t;
Subject: [Freesurfer] Cortical thickness using qdec (between scanners)
Hello FS experts,
I have a data set of 20 subjects (patients) collected at location-1 with 3T Siemens scanner. Also, I have a set of age-matched 20 subjects (controls) collected at location-2 with 3T Si
Hello FS experts,
I have a data set of 20 subjects (patients) collected at location-1 with 3T
Siemens scanner. Also, I have a set of age-matched 20 subjects (controls)
collected at location-2 with 3T Siemens scanner.
I am interested in comparing cortical thickness between controls and
patients us
