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.