Hi - it is only really finalPBVC that is meaningful. The other things are
intermediate measures:
AREA=brain "surface" area
VOLC=volume change
RATIO=ratio of the above, giving measure of mean distance surface has moved
PBVC=ratio, converted into % brain volume change
all the above is calculated forward and backwards, to avoid any bias and
reduce noise; the PBVCs are then averaged to give finalPBVC
Cheers, Steve.
On Thu, 31 Jul 2003, Stefan Christ wrote:
> Hi - I'got a problem with the meaning of the results in SIENA. After
> examining two brains, the results are published in
> the "<file1>_to_<file2>.siena - file. There is mentioned the finalPBVC -
> this is no problem - the meaning is clear. But there are also mentioned the
> values "AREA", "VOLC", "RATIO" and "PBVC" two times with different results.
> What exactly is the meaning of this results ? How can I use them ? How is
> the finalPBVC calculated ?
> Thanks a lot for your help.
> Stefan
>
Stephen M. Smith MA DPhil CEng MIEE
Associate Director, FMRIB and Analysis Research Coordinator
Oxford University Centre for Functional MRI of the Brain
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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