> This e-mail won't be quite as easy as the last. Sorry. Because I've also
> been having trouble with the orientation of our fMRI images, I've been
> following these e-mails (specifically about image orientation). Can you
> please tell me what LPI and RPI are?
LPI is left, posterior, anterior, and RPI is right, posterior, inferior. The
first element (L or R in this case) indicates the fastest changing direction
within the file. The last element (I in this case) indicates the slowest -
i.e. the way that the planes of data are stored.
Best regards,
-John
> Quoting John Ashburner <[log in to unmask]>:
> > > after John's emails I'd like to be sure about a couple of things.
> > > 1- What matters for flipping is the handness of storage, is that
> > > correct?
> >
> > Yes.
> >
> > > 2- Data stored in Right hand system needs not to be flipped, while Left
> > > hand stored data need to be flipped.?
> >
> > Yes.
> >
> > > 3- To tell the handnees of the actual
> > > data, John suggested to look at voxel (1,1,1) for axial images. Now if
> > > voxel (1,1,1) is LPI my data are right hand and need not to be flipped
> > > in x dimension. is that correct?
> >
> > Yes.
> >
> > > If voxel (1,1,1) is RPI data need to be flipped
> > > in x dimension. is that correct?
> >
> > Yes.
> >
> > > thanks for any help
> >
> > That was easy.
> >
> > best regards,
> > -John
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