Hi All,
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.
Thanks for the help.
HOWIE ROSEN
Howard Rosen, MD
Department of Neurology
Memory and Aging Center
University of California at San Francisco
350 Parnassus Avenue, Suite 501A, Box 1207
San Francisco, CA, 94143-1207
Ph: 415-476-6880
Fax: 415-476-4800
email: [log in to unmask]
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