Dear FSL experts,
I have recently run TBSS on 100 subjects. Then I used randomise to compare 2 groups: one with 45 subjects with cardiovascular risk factors and the other group with 55 subjects without cardiovascular risk factors.
The results showed that the group with cardiovascular risk factors had higher MD, RD and AD in some tracts, which makes sense to me. However, this group also showed higher FA in a few tracts, some of which overlapped with the tracts showing higher diffusivity.
How would you interpret these results? Is there any condition that leads to an increase of both FA and diffusivity measures?
Or do you think there are some problems with my images or that I should include some covariates in the analyses such as gray matter volume?