No, because it is not balanced. None of your subjects were scanned on the Prisma at baseline and on the Trio at follow-up 🙁 ________________________________ From: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu on behalf of Markus Gschwind markus.gschwind@gmail.com Sent: Friday, January 31, 2020 6:17 PM To: Freesurfer support list freesurfer@nmr.mgh.harvard.edu Subject: Re: [Freesurfer] Question longitudinal study about treatment effect with change of scanner and head coil?
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Thank you, Anastasia, that was my thoughts also. So there is no way regressing this out, right? Best, Markus
Le sam. 1 févr. 2020 à 00:10, Yendiki, Anastasia <AYENDIKI@mgh.harvard.edumailto:AYENDIKI@mgh.harvard.edu> a écrit : Hi Markus - If you were to find longitudinal changes in this study, you would have no way of knowing if they are changes in the brain or changes in the instrument used to measure the brain.
a.y ________________________________ From: freesurfer-bounces@nmr.mgh.harvard.edumailto:freesurfer-bounces@nmr.mgh.harvard.edu <freesurfer-bounces@nmr.mgh.harvard.edumailto:freesurfer-bounces@nmr.mgh.harvard.edu> on behalf of Markus Gschwind <markus.gschwind@gmail.commailto:markus.gschwind@gmail.com> Sent: Friday, January 31, 2020 6:04 PM To: freesurfer <freesurfer@nmr.mgh.harvard.edumailto:freesurfer@nmr.mgh.harvard.edu> Subject: [Freesurfer] Question longitudinal study about treatment effect with change of scanner and head coil?
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Dear experts,
I am reviewing a study that proposes a longitudinal study in patients across several years on the effect of medical treatment in terms of fcMRI and DTI-connectivity measures.
However, in several but not all patients, the scanner was upgraded from Trio to Prisma and the head coil was changed from a 12 to a 20-channel. Every patient had the upgrade at another time point.
I would like to hear your opinion on this. In my experience, the scanner upgrade and especially the head coil upgrade heavily affected the images.
So I have fundamental doubts about the feasibility. What would be the conditions under which it could be acceptable?
Thank you in advance! Best, Markus _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edumailto:Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer