This happens, and is a known artefact of fMRI that results from
de-phasing of the signal through the slice. It is especially prevalent
close to air cavities, and results from distortions of the magnetic
field due to differing magnetic susceptibilities of air, compared to
tissue, bone, water etc.
Speak to your local physicists for further advice.
Best regards,
-John
Hi,
I was going through the functional images visually using the
display function and noticed that there is a great amount of
signal dropout in the orbitofrontal area. It seems to have been
present even before I run any preprocessing steps but I was just
wondering, are there ways in which I can minimize this signal
dropout before conversion from DICOM to NIFTI? Could you advise
on this?
Thanks!
Karen
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John Ashburner <[log in to unmask]>
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