[Insight-users] MI and DeformationRegistration1

[Serena Fabbri]

Hi All,

I need some clarification about DeformableRegistration1.
I am registering MRI and CT of different patients with MI.
fixed: CT
moving: MRI

I don't understand very well the result.
The registered image is not deformed ....it appears just much more blurred than MRI original.

has anybody obtained the same behavior?
how much is deformation expected?
Is it a bad combination of parameter or maybe intersubject deformation is not possible with FEM?


here there is the parameter file. 
another question: I have selected DescentDirection= max for MI...is it correct or is it necessary to min ?

any help will be appreciate.
thanks.

Serena.


% --------------------------------------------------------- 
% Parameters for the single- or multi-resolution techniques 
% --------------------------------------------------------- 
1 % Number of levels in the multi-res pyramid (1 = single-res) 
1 % Highest level to use in the pyramid 
1 1 1 % Scaling at lowest level of pyramid 
4 % Number of pixels per element 
1.e2 % Elasticity (E) 
1.e2 % Density x capacity (RhoC) 
1 % Image energy scaling (gamma) - sets gradient step size 
2 % NumberOfIntegrationPoints 
1 % WidthOfMetricRegion 
200 % MaximumIterations 
% ------------------------------- 
% Parameters for the registration 
% ------------------------------- 
3 0.99 % Similarity metric (0=mean sq, 1 = ncc, 2=pattern int, 3=MI, 5=demons) 
1.0 % Alpha 
1 % DescentDirection (1 = max, 0 = min) 
2 % DoLineSearch (0=never, 1=always, 2=if needed) 
1.e1 % TimeStep 
0.5 % Landmark variance 
0 % Employ regridding / enforce diffeomorphism ( >= 1 -> true) 
% ---------------------------------- 
% Information about the image inputs 
% ---------------------------------- 
176 % Nx (image x dimension) 
256 % Ny (image y dimension) 
145 % Nz (image z dimension - not used if 2D) 
../Normal-093/1851_T1-Flash/MR/Affine/AR_MR.mha % Moving
../RIRE/102/patient_102_scale.mha %Fixed

% ------------------------------------------------------------------- 
% The actions below depend on the values of the flags preceding them. 
% For example, to write out the displacement fields, you have to set 
% the value of WriteDisplacementField to 1. 
% -------------------------------------------------------------------
0 % UseLandmarks? - read the file name below if this is true 
- % LandmarkFileName 
./T1_TEST % ResultsFileName (prefix only) 
1 % WriteDisplacementField? 
./T1_TEST_disp % DisplacementsFileName (prefix only) 
0 % ReadMeshFile? 
- % MeshFileName 
END