Mark,
The problem is that the phase orientations for the phase maps are different
(one is A/P, the other is R/L), so the resulting fieldmaps are nor
appropriate. When the fieldmap is applied it severely distorts the EPI, such
that part of the brain is pulled posteriorly and the other anteriorly. You
can tell this is what would happen just by looking at fieldmap, the
intensity values shift greatly in a linear fashion, e.g, values may start at
-500 on one side of the brain and end up at 600 on the other side .
My question is whether the phase information can somehow be reoriented?
Which doesn't seem possible, at least from my limited knowledge. Or whether
something else can be done?
Thanks.
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