Hi Daniel,
this looks like a wrap around in phase encoding direction. You can try to
unwrap this image (and probably the entire EPI series where this image
comes from) using the Volumes toolbox.
However, your FOV in AP direction seems to be very tight, I would
recommend a slightly larger one (either more voxels or larger voxel sizes)
- but don't change this if you are in the middle of a study!
Volkmar
On Tue, 22 Aug 2006, Daniel Simmonds wrote:
> Hi,
> The EPI image for one of our subjects has a strange error (or at least,
> strange to me). I think it is an aliasing error, but anyway, the anterior
> part of the brain is chopped off and placed in the back of the brain. I've
> attached one slice of this as a .tif file. Does anybody know of any way to
> deal with this, because when I try do a rigid coregistration of the
> individual high res anatomical to the EPI, the fit is thrown off, since the
> posterior of the anatomical extends out past the posterior of the EPI, to
> where the anterior part is moved. One solution I thought of is to draw a
> mask in MRIcro over the front of the brain (a few pixels thick over the
> black area where brain should be) and in back of the brain (where the
> anterior portion "bleeds" over). I cannot figure out how to use this custom
> mask to weight the EPI image (which serves as the template in the
> coregistration, since we don't want to reslice and smooth the data). Any
> advice? Thanks so much!
>
> Daniel Simmonds
> Developmental Cognitive Neurology
> Kennedy Krieger Institute
> [log in to unmask]
>
--
Volkmar Glauche
-
Department of Neurology [log in to unmask]
Universitaetsklinikum Freiburg Phone 49(0)761-270-5331
Breisacher Str. 64 Fax 49(0)761-270-5416
79106 Freiburg
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