Hi - the "brain percentage" is not a very useful number. the numbers of
interest are GREY WHITE and BRAIN. The problem with the CSF number is that
it also depends on the amount of peripheral CSF that BET includes - which
is why when you use the -r option you get the more useful output of
ventricular CSF.
Cheers.
On Thu, 15 Jan 2004, Stefan Christ wrote:
> hi- thanks for answer,
> I have got a reason to interpret this - how can I use it ???????
> And what's the meaning of brain percentage - is there any information in it
> I can use ???????
>
> Cheers, Stefan
>
>
> Hi - the numbers that you really want are those at the very bottom of the
> SIENAX output (ie at the end of the .sienax file). This gives you GREY and
> WHITE (and BRAIN, ie their sum) volumes after normalising for head (ie
> skull) size. Unless you have a reason for wanting to interpret CSF volume
> you should probably ignore that number.
>
> Cheers, Steve.
>
>
> On Thu, 15 Jan 2004, Stefan Christ wrote:
>
> > Hello,
> > one question: If I run SIENAX, I get some results, but I've got no idea,
> > what's the meaning of
> > 1.)CSF (I gueuss: cerebro-spinal-fluid, but how can I use this value? Is
> it
> > a value, I can use without any transformation ?)
> > 2.)tissue 1
> > 3.)tissue 2
> > 4.)brain percentage
> >
> > Thanks a lot for helping me
> >
> > Stefan
>
Stephen M. Smith DPhil
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
|