Dear Tetsuya:
I second the comments by Marco and Philipp. If
you are using the standard brain templates from
SPM these may not properly reflect the degree of
atrophy for elderly brains and contrast of your
images. I also wonder about the gray/white/csf
contrast in your images. Also a slight bit of
movement in the 4 subjects that failed to segment
properly might have been caused by enough added
enough noise to reduce image contrast.
Darren
At 11:15 PM 10/18/2005, Iidaka wrote:
>Dear expert.
>
>I am getting into trouble with optimized VBM and T1 images of elderly
>subjects. When hi-resoution (1.7 x 0.82 x 0.82mm voxel) images were
>segmented, gray and csf are not properly segmented. Seg1 image appears to
>include both grey and csf, and seg3 image has only outer brain tisssues.
>Please see an attached jpeg image. Among 11 brains processed, the miss-
>segmentation occured in four images. These four T1 images do not look very
>difefrent from other properly segmented images.
>
>Any help is very much appreciated.
>
>Tetsuya Iidaka
>Department of Psychiatry
>Nagoya University
>
>
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Darren R. Gitelman, M.D.
Cognitive Neurology and Alzheimer¹s Disease Center
Northwestern Univ., 320 E. Superior St., Searle 11-470, Chicago, IL 60611
Voice: (312) 908-9023 Fax: (312) 908-8789
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