Thank you a lot for your kindly help Matthew :-)

Happy Merry Christmas!!

Rosalia.

2015-12-16 17:41 GMT+01:00 Matthew Webster <[log in to unmask]>:

Hello Rosalia,

                          If native_image_subject_1 was a 4D file, consisting of subject-specifc white-matter segmentations, then yes the command below ( with -V ) will work. However, the filename implies that the image is just the input data for your first subject, in which case it is not appropriate. For each subject, a white-matter segmentation must be calculated for fslstats to process.

Kind Regards

Matthew

Hi Anderson,

Sorry for posting this again...but I would be sure about if I have to use fslstats -t native_image_subject_1 (with or without -V flag).

Thank you again for your patience.

Rosalia.

2015-12-16 11:05 GMT+01:00 Rosalia Dacosta Aguayo <[log in to unmask]>:

Hi Anderson,

If I have understood you well, one form to do this will be to get the native image of every subject (FA) and run:

fslstats -t native_image_subject_1 -V to get the volume without zeroes...right?

In the case I compute other maps (RA and AD) I should do the same, right?

Rosalia.

2015-12-16 10:47 GMT+01:00 Anderson M. Winkler <[log in to unmask]>:

Hi Rosalia,

I'm not sure about a paper that could be referenced (maybe others can help with examples), but the procedure itself consists of running fslstats to compute a global mean (or sum) across space for each subject, then including it in the model as an extra, nuisance EV.

The option -t (in fslstats) may be handy.

All the best,

Anderson

On 15 December 2015 at 14:58, Rosalia Dacosta Aguayo <[log in to unmask]> wrote:

Dear FSL experts,

Sorry if this is a simple question. I am working with DTI data with stroke patients and I would like to add as a covariate a global measure of white matter due to the fact that my stroke patients will have less white matter in some structures in comparation with my healthy controls...any advice or any paper where I could find the methodology described or any help in order how I can do this it would be highly appreciate.

Thank you a lot for you helping.

Merry Christmas for all the group.

Rosalia.