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, _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer [1] The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mai l contains patient information, please contact the Partners Compliance HelpLin e at http://www.partners.org/complianceline [2] . If the e-mail was sent to you in er ror but does not contain patient information, please contact the sender and prop erly dispose of the e-mail.
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