| I am using SPM for VBM analysis, and I am interested in the correction for
| the Jacobian parameters. I have tried it on a couple of brains and applied
| it to the normalized image, and noted an interesting phemomenon. In brains
| with a large degree of atrophy
| the segmentation done after the Jacobian-modulated process is much less
| accurate than a segmentation done before after normalization, but without
| Jacobian modulation. The gray matter is wider and less well-defined, and
| there is more 'noise' in regions such as the ventricle and the around the
| basal ganglia. Does this make sense?
|
| Since I am using the segmented images for VBM analysis, would it make any
| difference if I apply the Jacobian modulation to the segmented image rather
| than the normalized unsegmented image.
The modulation should be done on the grey matter segments, rather than the
normalised images themselves.
Best regards,
-John
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