Areas of Hyperintensity after SDC in fMRIPrep 24.0.1

Software Support
1

Summary of what happened:

Hello. I am preprocessing data using fMRIPrep version 24.0.1. What I noticed is that after applying SDC (Susceptibility distortion correction: FMB (fieldmap-based) - phase-difference map) that many participants have areas of hyperintensity in the OFC which darkens contrast in other regions. I have attached an example below. This is apparent in the sagittal slices. Thanks!

Version:

24.0.1

Environment (Docker, Singularity / Apptainer, custom installation):

Singularity

Data formatted according to a validatable standard? Please provide the output of the validator:

BIDS

PASTE VALIDATOR OUTPUT HERE

Screenshots / relevant information:

Screenshot 2026-07-23 at 5.19.29 PM
Screenshot 2026-07-23 at 5.19.29 PM1088×1086 297 KB

2

Hi @kmh6587 and welcome to neurostars!

Does this behavior persist with the most recent version?

Best,

Steven

3

Hi Steven,
I have not yet run fMRIPrep with the most recent version. Right now, I have access to 24.0.1 and would need to update to the newest version and check.

4

Hi @kmh6587,

Usually it is standard to check against the most recent version to know if this is a software vs. data issue, so I would start by trying to get access to 25.2.5 (most recent at this time). The SDCFlow software within fMRIPrep has since changed from 2.8.1 to 2.15.0. It is possible the changes in there could be relevant to you.

Best,
Steven

5

Thanks! I’ll do that and see if this fixes the issue.