Hi Stacey
we recommend processing all of your subjects the same way. Do you
understand why some would have a big bias field and some would not? It was
always the same coil, wasn't it?
cheers
Bruce
On Mon, 9 Jul 2018, STACEY M SCHAEFER
wrote:
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Hello Freesurfer experts,
Our current 3T T1s exhibit structural hyperintensities due to the inhomogeneity
of the receiver coil, but not all scans have
hyperintensity issues. The local MRI physicist suggests running
N4BiasFieldCorrection through multiple iterations prior to
Freesurfer processing on problematic scans.
We would like your opinion as to whether running a bias correction on the
individual problematic scans could introduce any
additional biases in Freesurfer processing. This is a longitudinal sample of ~
300 participants. Is it OK to run
N4BiasFieldCorrection on individual scans as needed? Or would it be better to
run the bias correction on all the scans (the
entire sample) routinely, even if they do not show hyperintensity issues so all
scans are processed similarly across the
sample? Or do you have any other suggestions?
Your guidance is much appreciated!
Thank you.
Stacey
Stacey M. Schaefer, Ph.D.
Center for Healthy Minds
University of Wisconsin-Madison
625 W Washington Ave
Madison WI 53703
608-263-9321
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