Dear all,

I am using Freesurfer longitudinal analysis to detect the relationship between the change of thickness in patients and a clinical test (ex: MMSE). I just have MRI of patients at two time points (baseline and followup) without normal control subjects. I have already completed longitudinal analysis following Freesurfer instruction. Now I am not sure how to design the FSDG file and contrast vector. I want to measure whether the change of thickness of patients (from baseline to followup) has some relationship with MMSE. Mean thickness of the brain is a covariate. The following is the FSDG and contrast I designed. Can anyone help me have a look whether it is right?

Thanks in advance!

Joe

FSGD:

GroupDescriptorFile 1

Title MMSEandthickness

Class Baseline

Class Followup

Variable MMSE mean_thickness

Input subject1 Baseline 21 2.6

Input subject2 followup 18 2.7

. . .

Contrast: 1 -1 0.5 0.5 0 0