Hi Miguel
the only way to rule out a consistent error that could induce a bias it
to visually inspect the results. That said, the image you show looks
fine. The white arrows are pointing to hippocampal gm, which is not
supposed to be captured by the surfaces. We don't include these regions in
our calculations of area/volume/thickness (except of course in hippocampal
volume)
cheers
Bruce
On Thu, 29 Nov 2018, Miguel Ángel
Rivas Fernández wrote:
External Email - Use Caution
Hi Bruce,
Effectively, I was referring to the big chunck of gray matter that is missing
from surfaces (I
attached another image). I have decided to revise the pial and white matter
segmentation again
because in the study that I am carrying out I found an "unexpected" or perhaps
not very frequent
result in the literature. I have compared general (eg BrainSegVolNotVent) and
specific (eg Middle
temporal, fusiform) measures of volume, thickness and area (Desikan-Killiany
atlas) between a
control group of healthy adults and two experimental groups, (single and
multiple domain Mild
Cognitive Impairment adults) using an ANCOVA (age, sex, years of education and
eTIV as covariates)
in external analysis (SPSS software). Results showed that control group present
a higher volume,
area and thickness than the multiple-domain MCI group (a result consistent with
previous studies).
However, no significant differences were observed between the control and the
single-domain MCI
groups. Specifically, the single-domain MCI group showed an equal or even
higher mean volume,
thickness and area than the control group in sevaral ROI´s. Given this
situation, we have decided to
review the recon-all's output again in order to verify that there is no error
that is influencing
this last result.
Could there be an error in the recon-all output that may be influencing these
results? Could you
suggest some procedure to check the output of the recon-all? I fixed skullstrip
as well as pial and
white matter surface errors when it was necessary. In the next few days I will
analyze this data
using QDEC.
Any recommendation will be very appreciated.
Thanks in advance,
Cheers,
El jue., 29 nov. 2018 a las 16:40, Bruce Fischl (<fis...@nmr.mgh.harvard.edu>)
escribió:
Hi Miguel,
not sure exactly where you mean, but the big chunk of gray that is
missing from the surfaces is probably hippocampus (so not a problem, since
it is not neocortex)
cheers
Bruce
On Thu, 29 Nov 2018, Miguel Ángel Rivas Fernández
wrote:
>
> External Email - Use Caution
>
> Hi Freesurfer devs,
>
> I´m doing a visual quality control of my pial and white matter
segmentation using
freeview and I
> noticed that several subjects could present an error in pial surface
segmentation. I
have attached
> two images.
>
> Is this an pial surface error? in that case, How can I fix it? maybe
adding control
points in order
> to extend the pial surface limit?
>
>
> Thanks
>
> Cheers,
>
>
> --
> Miguel Ángel Rivas Fernández
>
>_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
--
Miguel Ángel Rivas Fernández
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
