Dear all,

Im currently running a cortical thickness longitudinal analysis on a group of 50 patients. The difference between timepoints is less than 4months, so I do not expect large ageing effect (although there might be some). I would like to test for specific cortical changes after neurosurgery. I have read that it is not possible to run one-sample ttest within qdec, what alternatives do I have then.

- Could I just compute the average change in pc1 or rate?

- Would it then be advisable to run a paired-ttest analysis between timepoints instead of merging the images using long_mris_slopes?

Any advice would be appreciated.

Best,

José