Hi, we had the same problem and I'd highly recommend using some
"inhomogeneity correction" on the EPI scans before normalization.
Generally this correction nicely wraps the "blown-out" frontal lobe
back into a reasonable shape.
Good luck,
Tugan
At 9:58 PM +0000 11/9/01, Glenn Wylie wrote:
>Hello all,
>
>We've recently run into a problem using SPM to normalize functional scans
>acquired on our 3T magnet. Because it's a 3T, we get 'blow-out' of
>orbital, frontal cortex due to the nasal sinuses. This means that the
>brains we acquire have a peculiar shape (no orbital cortex). When we go to
>normalize these, SPM warps them into standard space -- but SPM doesn't know
>that they have no orbital cortex. This results in distortions: much of
>the brain is dragged anterior and inferior to where it really should be.
>
>The stuctural scans are not affected in the same way, and they normalize
>correctly. However, applying the parameters determined by normalizing the
>structurals to the functionals results in much the same problem.
>
>Does anyone have any fixes for this sort of problem?
>
>Many thanks,
>
>Glenn Wylie.
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L. Tugan Muftuler, Ph.D.
Health Sciences,
Research Imaging Center
Irvine Hall 164
University of California
Irvine, CA, 92697-5020
Tel: (949) 824-6290
fax: (949) 824-3481
E-mail: [log in to unmask]
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