Thank you.
Yes, I mean, I can find in literature several methods
to estimate T1w and T2w lesion volumes. I guess the ones estimated from
FS are the sum of these non-wm- and wm- hypointensities values (and not
just wm-hypointensities), and are referred as T1w lesion volumes since
the segmentation was based on T1w images.
Usually in healthy subjects
nobody refers any value (in literature), so I suppose that authors just
ignore the fact that FS has estimates of this measure also for controls
(even if it's False Positive, or other reason).
Cheers
Em 2016-02-13
21:03, Bruce Fischl escreveu:
> It depends what you want. If you want
total volume, then yes. They are
> typically false positives in young
healthy subjects. Telling damaged
> white matter from say the
superior-most aspect of the caudate is *very*
> hard on just a T1
> On
Sat, 13 Feb 2016, Otília wrote:
>
>> Thank you for your reply. I just
wasn't expecting ("high") values in healthy subjects. Of course FS just
"sees" voxels, whether it's a lesion or other thing, but I was afraid it
would be some segmentation issue. I have also other MRI contrasts but I
really wanted to estimate possible T1w lesion volumes. That's why I
asked for some references, and to understand the difference between
"wm-hypointensities" and "non-WM-hypointensities". Should I sum both
when referring to "T1w lesion volume"? best regards Em 2016-02-11 17:30,
Bruce Fischl escreveu: you can turn this off with the -nowmsa flag I
believe in recon-all. The labels are for damaged white matter and
damaged gray matter, which can be tough to distinguish based only a T1.
We have some (not-yet-distributed) tools that do pretty well on this if
you have other contrasts like T2/FLAIR/PD. cheers Bruce On Thu, 11 Feb
2016, Otília wrote: Greetings, I am wondering if there is some
information regarding the meaning of "wm-hypointensities" and
"non-WM-hypointensities" variables from the aseg.stats file, ie, what
features are included in these variables and how FS computes them. I
checked previous posts that have the same issue I have now. I find some
non-zero, (some cases have "quite big") WM-hypointensities values for
healthy young brains. I find it odd. I would appreciate some additional
information about these issues. Thank you! Best regards,
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