What is the prurpose of fmriprep --longitudinal flag?

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Hi, Finally I just started my research design. Im trying to adjust few fmriprep options for my data.(Of course, bids validated)

I have many question tho, but main question is what is the exact purpose of --longitudinal flag? In case of my dataset, I do not have multiple session, it only consist of 1 session of anatomical and functional image.

In case of my data, should I use --longitudinal flag? Objective of my research is that to find difference between patient and HC(Healthy control).

I think in my case, it wouldn’t be necessary but im always open for new opinion!!!

Best,
Junyong Oh

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Hi @dhwnsdyd21 ,

In case of only one T1w image per subject, you do not need to use --longitudinal flag and if you do, it will not change anything to your results.

Explanation:
https://fmriprep.org/en/stable/workflows.html#longitudinal-processing

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I see. Can I ask you one more? If I use --longitudinal flag, it automatically use mri_robust_template to make T1w template right?

The reason for making for t1w template using mri_robust_template is that T1w images might include noises or artifact right?

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mri_robust_template is used to average several T1w images together. There are other step in the anatomical workflow of fmriprep that will take care of the noise or the bias correction for instance.

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