Dear Freesurfer experts,

I am doing an analysis on a large data set gathered from eight different imaging centres. In my analysis I would like to covary for the imaging site but qdec only allows me to covary for categorical variables if they have two levels (and I have eight). I am also using age (continuous) and gender (categorical, two levels) as covariates.

Is there a way of using the imaging site as a covariate using qdec? Do you have any suggestions on how I should proceed? Is treating imaging site as a continuous variable acceptable?

Best wishes,

Hanna​