Susceptibility distortion correction (SDC) using Spin Echo Fieldmaps


I pre-processed resting state data using fMRIprep 20.1.1. This data set contain 20 subjects, 2 sessions for each subject, and 4 runs for each session. I used SpinEcho field maps to do the susceptibility distortion correction (SDC). The SDC with SpinEcho’s worked for majority of the data. However, it worsen the SDC’s in certain subjects. Below is the command that I used to run fMRIprep;

singularity run --cleanenv --bind /mnt/fMRIprep /mnt/tools/fMRIprep_sing/fmriprep-20.1.1.simg /mnt/fMRIprep/scR21 /mnt/fMRIprep/scR21_outputs -w /mnt/fMRIprep/scR21_outputs/derivatives/scratch --fs-license-file $PWD/license.txt --write-graph --cifti-output 91k participant --participant-label 50015 50016 50020 50024 50027 50033 50042 50137 50144 --ignore slicetiming --output-spaces T1w MNI152NLin2009cAsym:res-2 fsaverage fsLR

I am wondering if anybody else has experienced similar issues. Please let me know.

Thanks in advance
Best Regards