[Insight-users] 3d multi-modality registration

[Karthik Krishnan]

Hi Grace,

The correct use of image registration is to bring it close to final
solution and expect image registration to take it from there. I you
provide two volumes with vastly differnt extents and a poor
initialization, it wouldn't be surprising if registration failed to
achieve results. 

In a clinincal workflow, I don't think any radiologist/clinician would
perform registration using command line tools and proceed to the next
step without validating the quality of the registration. This is why its
usually done using GUI tools. For instance
InsightApplications/LandmarkInitializedMutualInformation (have you tried
this application for your datasets ?) allows you to place landmarks on
the source and target image, so you can roughly overlay the images
(usually within 0-5 mm of each other) and then allow registration to
fine tune it. If the overlay looks good, you are happy. 

Please give this application a try first :

1. Specify a landmark on the fixed and moving image. Pick  anatomical
correspondances. For an MRI of the brain, you could pick the tips of the
splenium of the corpuscallosum on a sagittal/coronal acquistion (you can
see it very clearly in Insight/Examples/Data/BrainMidSagittalSlice.png).
For an axial MRI, you could pick the tips of the ventricles.

2. Initialize using landmarks. (it should be one of the options on the
initialization menu). 

3. Register

Does this work for you ?

HTH
karthik

On Fri, 2006-05-26 at 12:26 -0400, Grace Chen wrote:
> Hi Luis,  Thanx a lot for your inputs!
> 
> I've been struggling with this one for a longest time....  The problem is
> that I have two 3D brain images and one brain image has greater physical
> extents in z.  The information of the two volumes are as follows:
> 
> Fixed image:
>   origin = [-120, -135.805, -29.7683]
>   spacing = [0.9375,  0.9375,  7]
>   extent = [256,256, 7]
> 
> Moving image:
>   origin = [-142.5, -170.488, -84.8781]
>   spacing = [1.17188, 1.17188, 5.5]
>   extent = [256,256, 28]
> 
> For these two brain volumes, the fixed image matches a section in the moving
> image...I tried registered them using the whole volume, the first slice of
> the registered moving image doesn't looked like that of the fixed image at
> all...Then, I tried extracting a section from the moving slice and
> registered them together....but the middle slices of the the registered
> image does not match the corresponding slices in the fixed image.  What's
> going on??  Is there prerequisite on the input data for performing
> mullti-modality registration using ITK?
> 
> Please help!!  I am in deperate need to really nail this this time!!  Thanx
> a million!!
> 
> Grace
> 
> ----- Original Message ----- 
> From: "Luis Ibanez" <luis.ibanez at kitware.com>
> To: "Grace Chen" <Grace.Chen at swri.ca>
> Cc: <insight-users at itk.org>
> Sent: Thursday, May 25, 2006 9:58 PM
> Subject: Re: [Insight-users] 3d multi-modality registration
> 
> 
> >
> > Hi Grace,
> >
> > In principle, that's true,
> >
> > but in practice it may not happen if the spatial extension
> > of the moving image doesn't fully overlap with the fixed
> > image.
> >
> > Have you checked the other slices ?
> >
> > Do they overlap well ?
> >
> >
> >      Luis
> >
> >
> > ===================
> > Grace Chen wrote:
> > > Hi there,
> > >
> > > My program performs the 3D multi-modality registration for two volumes.
> > > After the registration has been performed, is it true that the first
> > > slice of the registered moving image should look like the first slice of
> > > the fixed image?
> > >
> > > Grace
> > >
> > >
> > > ------------------------------------------------------------------------
> > >
> > > _______________________________________________
> > > Insight-users mailing list
> > > Insight-users at itk.org
> > > http://www.itk.org/mailman/listinfo/insight-users
> >
> >
> 
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