Dear SPM:
I want to segment EPI images to provide a grey-matter mask for restricting
a calculation.
I assume that the 4 segments correspond to grey, white, csf and other
stuff, and that the voxel values correspond to the probability that a voxel
belongs to a particular segment.
1) Is the algorithm likely to under or overestimate voxels as part of a
segment or is that known? Is it different for different segments?
2) Is there some threshold to choose to optimize a voxel as belonging to
grey matter, or is this empirical? I guess choosing everything above 0 in
that segment maximizes the amount of possible grey.
Thanks,
darren
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Darren R. Gitelman, M.D. E-mail: [log in to unmask]
Cognitive Neurology and Voice: (312) 908-9023
the Alzheimer's Disease Center Fax: (312) 908-8789
http://www.brain.nwu.edu
Northwestern Univ., 320 E. Superior St., Searle 11-470, Chicago, IL 60611
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