Closed julfou81 closed 10 months ago
Do both sequences have enough b>0 images for eddy to run?
Also, you can keep both AP and PA scans in the dwi/ directory and use the --separate-all-dwis
to have them processed on their own.
Thank you for the tip!
Yes both sets in AP and PA consist of 109 volumes total, of which: 7 b=0, 6b=300, 32 b=1000 and 64 b=2000.
For running each subset separately, I rebuilt a BIDS tree by putting the only b=0 in opposite direction in a fmap/
folder, renaming them with _epi
suffix and filling the json file with IntendedFor
field. This was working well for the PA set (with the b0 AP put in the fmap/
folder), but eddy crashes for the second set (full AP in dwi/
folder and PA b0 in fmap/
folder).
When you use --separate-all-dwis
, does topup uses the b0 from the other set to run?
yes, it will look in the dwi files to see if any have b=0 images that are suitable for distortion correction. Don't bother putting anything in the fmap/ directory
I noticed something interesting when trying to use --distortion-group-merge
and --separate-all-dwis
for my dataset with the same set of directions repeated for both encoding direction (AP and PA):
FileNotFoundError: No such file or directory '/work/temp_data_DWImergenone_PhantomPainBrain/qsiprep_wf/single_subject_CTS02_wf/dwi_preproc_ses_BRpre_dir_PA_wf/hmc_sdc_wf/eddy/eddy_corrected.nii.gz' for output 'out_corrected' of a ExtendedEddy interface
fmap/
folder where I extracted the b0s for each dwi set (7 for each PE direction), renamed them with _epi
suffix and use ÌntendedForfields to specify for which data each b0 is attributed (
b0_APfor _dir-PA_dwi and
b0_PAfor
dir-AP_dwi`). In that case, qsiprep is completed with no error, topup is run but the resulting preprocessed dwi images is a concatenation of both AP and PA dwi volumes.This should be fixed in recent releases
This an issue for a dataset for which we acquired the same set set of directions in AP and PA. QSIPREP worked fine for the full data set. For the sake of tests, I am trying to compare it with the dataset in AP only (corrected for topup with the b0 PA), and the dataset in PA only (corrected for topup with the b0 AP). QSIPREP worked well with the PA set but failed systematically for the AP set.
I am using qsiprep version 0.16.0RC3 with singularity on HPC using slurs: The exact same qsiprep and slurs settings setting was working well for several subjects and the other set of data of the same subject as I was explaining above
Command:
eddy_params.json file:
output log:
error log:
To better understand why eddy is crashing, I tried to launch eddy_openmp on my personal laptop (FSL 6.0.5) on the same data prepared by qsiprep (exact same files) and here is the output: