I haven't had any trouble tracking arcuate fibres using the default
curvature threshold (0.2) but if you're worried about it, just set it to
something really small like 0.01.
In my own experience, arcuate fibres tend to be on the edge of white matter
paths and thus seeds nearest to gray matter are most likely to reveal
these. I tend to anatomically mask a region and then selectively choose
"gray matter" voxels as the seeds by doing a fast-segmentation, computing
the tissue class probabilities, thresholding the grey matter image at 0.2
and binarising it to create a grey matter mask. If you then mask the
original anatomical image with the gray mask, you'll get the voxels with at
least 20% chance of being gray matter in your anatomical ROI. The ones
most likely to give good arcuate traces seem to be those closest to the
edge, although this is just anecdotal -- I haven't systematically looked at
this.
Cheers,
Joe
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Joseph T. Devlin, Ph. D.
FMRIB Centre, University of Oxford
Headley Way, Headington
Oxford, OX3 9DU, UK
Phone: +44-(0)1865-222-494
Fax: +44-(0)1865-222-494
Email: [log in to unmask]
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