Sorry to bother you again!
I use the default operation, -center DIFF. I did not demean the covariates. Is it correct?
Just like you wrote, the first two sub-bricks ( setA mean, setA Tstat) are for the group effect controlled at the center values of the two covariates. The next two (setA age-mean, setA age-Tstat) are for the marginal effect (slope) of age. And the last two are about the slope of blood test.
There is not sub-brick that is correlation coefficient between image and blood-test after remove the age effect, right?
Thanks,
Xiaozhen