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<div> Dear All,<br>
<br>
When I was trying to apply Jacobian modulation on nonrigid registered <br>
(SymmetricforceDemon) repeat scan, I found that the modulated image <br>
(voxel intensity * det(Jacobian)) does not look realistic but the <br>
registration result is almost perfect from image subtraction. The <br>
nonrigid registration and Jacobian modulate was done in both binary <br>
(segmented white + grey matter) and in original (full range intesity, <br>
skull stripped). In original image, there are some high intensity voxels <br>
around white matter region so the modulated image looks awkard. The <br>
intensity range of deteminant of Jacobian with the original is [-6.72, <br>
3.743] and with segemented image is [-0.49, 2.899]. The smooth options <br>
in SymmtricDemon were all turn on and tried various StandardDeviation <br>
settings. The Strange thing is that the deformations within white matter <br>
region is really noisy (I have appplied Histogrammatch and bias <br>
correction before NR starts), which is not I am expecting in the <br>
homogeneous region.<br>
And then I took divergence and norm image from deformation field, I <br>
found that the divergence and norm over the white matter region are much <br>
greater then venticle region (I am trying to measure longitudinal <br>
difference).<br>
<br>
I've also tried LevelSet and Bspline registration. THe deformation field <br>
and registraion results are almost as good as baseline scan like <br>
Demons.The defromation fields are totally different from each other. In <br>
T. Rohlfing's paper [1]. Although the det(Jac) are diffrent from various <br>
methods but the Jacobian integration does correpond the volume <br>
difference. But I just cannot get similar result!<br>
<br>
I really cannot figure out why, so can someone give me some advice?<br>
<br>
Thank you very much.<br>
<br>
*[1] T. Rohlfing*, “Transformation model and constraints cause bias in <br>
statistics on deformation fields,” in /Medical Image Computing and <br>
Computer-Assisted Intervention - MICCAI 2006: 9th International <br>
Conference, Copenhagen, Denmark, October 1-5, 2006, Proceedings/, R. <br>
Larsen, M. Nielsen, and J. Sporring, Eds., Berlin/Heidelberg, 2006, vol. <br>
4190 of /Lecture Notes in Computer Science/, pp. 207-214, Springer-Verlag.<br>
<br>
<br>
<br>
<br>
Best<br>
John<br>
<br>
<br>
</div>
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