# Synb0 for dwifslpreproc: How?

**URL:** https://community.mrtrix.org/t/synb0-for-dwifslpreproc-how/6386
**Category:** Uncategorized
**Created:** [February 9, 2023, 3:16pm UTC](https://community.mrtrix.org/t/synb0-for-dwifslpreproc-how/6386 "2023-02-09T15:16:14Z")
**Posts on this page:** 1
**Showing post:** 3

<div class="post-metadata">

### Author: ![AmirHussein](https://community.mrtrix.org/user_avatar/community.mrtrix.org/amirhussein/32/5014_2.png) [@AmirHussein](https://community.mrtrix.org/u/AmirHussein)
#### Post date: [February 20, 2023, 12:25pm UTC](https://community.mrtrix.org/t/synb0-for-dwifslpreproc-how/6386/3 "2023-02-20T12:25:51Z")

</div>

Hi Fiona,

Thanks for your reply, and yes, I am having the same struggle as yours most possibly due to the interactions of strides between T1 and b0s. The pipeline I used generated topup\_fieldcoeff.nii.gz with anterior-posterior being reversed (see below; look for the eyeballs in posterior!). I am not sure whether Left-Right was also distorted or not. This resulted in an extreme distortion in the preprocessing step.

 ![image](https://community.mrtrix.org/uploads/default/original/2X/a/a0bb05747d41dbcd04007bfacb1927bd2ca8c7ce.png)

So, what I did was to run `fslreorient2std` on both b0 and T1 in the INPUT folder, rerun Synb0 without any flags, and then pass the topup outputs to the dwifslpreproc.

The results are so far so good!

Amir

---

_[View the full topic](https://community.mrtrix.org/t/synb0-for-dwifslpreproc-how/6386)._