Re: [Freesurfer] Cortical thickness using qdec (between scanners)

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 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, 2016 at 12:02 PM, Douglas N Greve <greve@nmr.mgh.harvard.edu mailto:greve@nmr.mgh.harvard.edu> wrote:

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 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 using FreeSurfer but I am not sure if I can do that since I
> have both the data sets collected at two different locations.
>
> I would really appreciate any inputs on this.
>
> I tried to find some papers on scanner differences but all I could
> find was between 1.5 T vs 3T or 3T vs 7T. Is there any special
> covariates I need to define for this purpose (if so then at
which step
> during analysis?) or is it not possible at all?
>
> Thanks.
>
>
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