QSIPrep does distortion correction with different PE directions?

[akelkar26]

Hi, I am opening this issue to confirm qsiprep does distortion correction correctly on my data. I have two datasets I am working with

Dataset 1: patient data (stroke) where I use dwi-only flag. We collect the following scans: Multi-shell DTI data: Echo time = 82ms; TotalReadout time = 0.0644004 sec, PE direction: A>>P

Blip-up scan: Echo time = 96ms; TotalReadout time = 0.106945 sec, PE direction: R>>L

I am using version 0.13.0RC1 I was unsure from documentation, can PEPOLAR use R>>L PE direction for distortion correction? I get no error or no crash log.

However, from documentation it says: Currently, different phase encoding dimension in the target file and the ‘_epi’ file(s) (for example ‘i’ and ‘j’) is not supported.

The output however, seems fine.

I also have a second dataset conforming to the conventional PE directions

Dataset 2: entire anat and dwi pipeline run Multi-shell DTI data: Echo time = 82ms; TotalReadout time = 0.0644004 sec, PE direction: A>>P

Blip-up scan: Echo time = 82ms; TotalReadout time = 0.0644004 sec, PE direction: A>>P

Blip-down scan: Echo time = 82ms; TotalReadout time = 0.0644004 sec, PE direction: P>>A

From documentation it seems like it takes the blip-up and blip-down scan for susceptibility distortion correct. Is that correct? Here is the output from that data. It also looks good.

Could you please confirm the PEPOLAR Pipeline can handle both these use cases?

Thank you so much Best, Apoorva

[akelkar26]

Hi, I am just reaching out to confirm the PEPOLAR Pipeline can handle both use cases noted above? Your feedback is appreciated. Thank you Best, Apoorva

[mattcieslak]

Hi Apoorva, I can't tell from the static image if it's working or not. For your AP/PA data you will get distortion correction applied as long as the BIDS is configured correctly. I've never tried AP/RL before, but I think if you have the IntendedFor set in the sidecar of the RL file it may work