Hi - thanks for your email.
SIENA is measuring change in total brain volume and SIENAX is measuring
normalised brain volume - neither is designed to measure lesions I'm
afraid - both will normally count lesion as brain matter.
You may be able to find lesion volumes by first using BET to extract the
brain and then using FAST to segment the resulting brain image - you will
probably have to specify exactly how many classes you want (ie for lesions
this will be one more than the number of "normal" appearing tissues). This
analysis can be run inside or outside of MEDx with the BET and FAST GUIs.
Hope this helps - Steve.
Stephen M. Smith
Head of Image Analysis, FMRIB
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
On Tue, 14 Aug 2001, QingYan Guan wrote:
> Hi,
>
> I tried to estimate the lesion volume in brain using siena and sienax. But
> both program didn't give the information that I want. The second time point
> brain volume was even got smaller than first time point.
>
> Another question is, when I tried to modify the segmentation of brain, I
> segmented manually the part of lesion as white matter, then how can I
> define all other brain part as gray(or sth)? Is there a option for sienax to
> have more than 3 classes of tissues? Or is there any way to get region of
> lesion without using MEDx?
>
> Any other method or point for lesion analysis?
>
> Thanks a lot!
>
> Best regards,
> Qingyan
>
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