Thank you very much for your answer Bruce !

have a nice evening,

Alex.

Le 3 juin 14 7:6, Bruce Fischl a écrit :

Hi Alex

I would think that longitudinal analysis is still the way to go as we try to improve both reliability and sensitivity using the fact that we have multiple scans/subject.

cheers Bruce On Tue, 3 Jun 2014, Alexandru Hanganu wrote:

...

Hello Everyone,

could someone please give us an advice about which method you consider is the best for our study ?

we have two groups with MRI at Time 1. Each group received medication. After this we performed another MRI at Time 2 after 2 weeks.

The best method for this study is a longitudinal one or a cross-sectional GLM ?

We consider that the distance between the time points is too small, and the longitudinal method is not the best choice. Hence, this study should be treated as a cross-sectional one. In this case we think about performing a simple GLM with the contrasts: 0.5 0.5 0.5 0.5 or 1 -1 -1 1

for the groups:

1. grp 1 time 1
2. grp 1 time 2
3. grp 2 time 1
4. grp 2 time 2

we are searching to see whether medication had any impact on the cortical morphology in each group and between the groups.

Thank you ! Best regards, Alex.

---

Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer

The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.