[Insight-users] Registration of one sub-brain to full-brain

[Erik Tuerke]

Hi!

I want to register one hemisphere (actually 30 slices of 0.75 mm) to a 
fullbrain scan (30 slices of 0.75mm, but shifted to superior for about 5 
mm) . Currently i am using a MattesMutualInformationImageToImage metric, 
a RegularStepGradientDescentOptimizer and a VersorRigid3DTransform.

Prior to the registration the hemisphere is roughly aligned to the 
fullbrain (only needs translation of few mm and little rotation). If i 
start the registration the optimizer finishes with a rotation of about 
90 deg x and y. I also tried a VersorRigid3DOptimizer and a 
NormalizedCorrelation with almost the same result.

The scalefactors of my optimizer are:
                optimizerScaleRegularStepGradient[0] = 1.0;
                optimizerScaleRegularStepGradient[1] = 1.0;
                optimizerScaleRegularStepGradient[2] = 1.0;
                optimizerScaleRegularStepGradient[3] = 1.0/1000.0;
                optimizerScaleRegularStepGradient[4] = 1.0/1000.0;
                optimizerScaleRegularStepGradient[5] = 1.0/1000.0;

I guess the itk examples are proposing the same values.
Is there any trick to apply such a sub-brain registration to a 
full-brain registration. The worrying thing is that SPM gets it right :-(

Thanks and best regards!!

-- 
Erik Tuerke
Department of Neurophysics 
Max-Planck-Institute for Human Cognitive and Brain Sciences
Stephanstrasse 1A
04103 Leipzig
Germany 
Tel: +49 341 99 40-2440
Email: tuerke at cbs.mpg.de
www.cbs.mpg.de