As stated in the documentation, T2 or FLAIR images in input BIDS directory should be used automatically in the Freesurfer recon-all pipeline to help define pial surface.
However, having a FLAIR image in my input BIDS directory, this wasn’t take into account when Freesurfer recon-all process was launched.
Is there anything to do to force the use of such data ?
How are you running fMRIPrep? Docker/Singularity or manual python installation?
Without more details, I would be inclined to think that fMRIPrep is not finding the FLAIR images for some reason. Please, also double-check on logs under the freesurfer/ output folder to confirm that indeed, FLAIR were not used.
EDIT: also make sure you are not re-using pre-cached freesurfer results without FLAIRs.
One more thing to check is whether you are using pre-cached freesurfer results. Could it be that you ran it without FLAIR and now fMRIPrep is just reusing those results?
The syntax for using Flair in Freesurfer is not very intuitive. It is not enough with just writing
-FLAIR . You also need to include -FLAIRpial in the recon-all call.
That’s right but it is similar with T2 images where both -T2 and -T2pial flags have to be specified in recon-all pipeline.
However concerning the automatic use of FLAIR images in the anatomical pipeline of fMRIPrep, it seems that BIDS FLAIR input is taken into account but not when launching recon-all process.
So this is a very late response, but I wanted to ask if people experiencing these problems are using high(ish)-resolution FLAIR images? We ignore FLAIRs with >1.2mm voxels on the recommendation of FreeSurfer developers. I’m not seeing this as part of this discussion, and I wonder if we failed to consider this case.