FATCAT_MVM with 'within-subject factor'

I have some questions about group-level DTI analysis. I have .grid files from each subjects. I want to run group-level analysis with them.

1-1) I am going to use FATCAT_MVM for this. I need to run fat_mvm commands with .grid files and . csv files.
My experiment is looking at the longitudinal study with medication effect, for example, subj01 in group A has been scanned four times at week 1, 2, 3 and 4, and I want to see medication effect via DTI tractography changes.
To see the effect of time and the effect of group x time, gender and race can be between-subject factor, but ‘time (week 1, 2, 3, or 4)’ should be within-subject factor.
As I know, 3dMVM can not run with within-subject factor, so we need to run 3dLME for this. But we only have fat_mvm for 3dMVM.
How can I run the group level DTI analysis with within-subject factor?

1-2) I have experience to run 3dLME with beta image not DTI grid files. Is there any way to run 3dLME with .grid file directly instead of using beta image?

  1. Also I want to run fat_mvm with functional connectivity matrix from resting state fMRI.
    Usually, fat_mvm uses *.netcc files for functional connectivity matrix. But in my case, I didn’t use 3dNetCorr to get functional connectivity matrix, and I have only my own functional connectivity matrix(excel file).
    I don’t know how *.netcc files look like. Do you have any idea to convert my own functional connectivity matrix(actually this is just excel sheet defined by 'ROI by ROI’ matrix) to some files which can be used as the input of fat_mvm?