Another note of caution is that brains are not entirely symmetrical,
structurally or functionally. So flipping MRI images may not result in a
spatially homogenous data set for your analysis even though they are
consistent in terms of the lesioned hemisphere. One option to address the
lack of anatomical asymmetry is to flip epi images prior to normalisation
and then normalise using symmetrical priors. (See Didolet et al, 2010 for an
example creating a symmetrical template). Others on this list might have
more detailed information but this approach may create additional problems
with normalisation routines and anatomical labelling/ROI analyses and
doesn't address the issue of functional asymmetries.
Cheers
-Bill
> -----Original Message-----
> From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]]
> On Behalf Of Michael Harms
> Sent: Saturday, 26 February 2011 1:20 AM
> To: [log in to unmask]
> Subject: Re: [SPM] script to flip MR images left to right (or vice
> versa)
>
> A note of caution about using fslswapdim in this manner however:
> If you do that, the data order and the header information stored in the
> sform/qform will no longer be in sync. So, what the sform/qform defines
> to be "left" will no longer be the subject's true left (assuming the
> labels in the original data were correct)!
>
> Read the following FSL page if you want all the details:
> http://www.fmrib.ox.ac.uk/fsl/avwutils/index.html
>
> Best,
> -MH
>
> On Fri, 2011-02-25 at 11:54 +0000, Rosa Sanchez Panchuelo wrote:
> > You can do it easily with fsl:
> > fslswapdim input_image.img -x outpu_image.img
> > -x will flip the image in the RL direction.
> >
> > On 25/02/2011 11:39, Richard Morris wrote:
> > > I'm not sure, but I think you can use the image calculator in SPM,
> > > with the following function:
> > >
> > >
> > > f = 'Inv(i1)'
> > >
> > >
> > >
> > > On 25/02/2011, at 10:16 AM, Michael T Rubens wrote:
> > >
> > > > how about this:
> > > > %%%
> > > >
> > > >
> > > > v = spm_vol('/image_path/brain.img');
> > > > x = spm_read_vols(v);
> > > >
> > > >
> > > > x = x(size(x,1):-1:1,:,:);
> > > >
> > > >
> > > > [path file] = fileparts(v.fname);
> > > > v.fname = fullfile(path,['flipped_' file');
> > > >
> > > >
> > > > spm_write_vol(v,x)
> > > >
> > > >
> > > > %%%
> > > >
> > > >
> > > >
> > > >
> > > > cheers,
> > > > michael
> > > >
> > > > On Thu, Feb 24, 2011 at 9:35 AM, Chien-Ho Lin
> > > > <[log in to unmask]> wrote:
> > > > Hi,
> > > >
> > > > I stuides patients with stroke doing some behavior
> > > > paradigm in fMRI.
> > > > Patients always used their affected limb for the task so
> > > > some patients used left hand some used right hand.
> > > > Now I would like to flip the left and right of the images
> > > > so patients' lesional hemisphere are on the same side.
> > > >
> > > > Is there any script in spm 5 or 8 can help to accomplish
> > > > this goal?
> > > >
> > > > I found a m file called spm_flip.m but it seems support
> > > > only spm2.
> > > >
> > > > Your assistance are well appreciated.
> > > >
> > > > Thank you so much.
> > > >
> > > > Janice
> > > >
> > > >
> > > >
> > > > --
> > > > Research Associate
> > > > Gazzaley Lab
> > > > Department of Neurology
> > > > University of California, San Francisco
> > > >
> > >
> > >
> >
> >
> > --
> > Rosa Maria Sanchez Panchuelo
> > Post-doctoral Research fellow
> > Sir Peter Mansfield Magnetic Resonance Centre
> > University of Nottingham
> > University Park
> > Nottingham, NG7 2RD
> > United Kingdom
> > +44 115 84 66003
> >
> >
> >
> >
> >
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