External Email - Use Caution
A couple of questions:- 1) Do you experience similar variability with the T2 and FLAIR options or is FLAIR more variable due to it's generally lower SNR? 2) Should the spatial resolution of the T2/FLAIR scan match that of the T1 scan?
Richard
Message: 8 Date: Wed, 17 Mar 2021 17:51:51 -0400 From: "Douglas N. Greve" dgreve@mgh.harvard.edu Subject: Re: [Freesurfer] Which pial surface to trust, with or without -FLAIR option To: freesurfer@nmr.mgh.harvard.edu Message-ID: 3c789103-dad7-974a-0d76-58a02cba2992@mgh.harvard.edu Content-Type: text/plain; charset="utf-8"
We get a lot of variable results with FLAIR. Sometimes it helps, sometimes it hurts. FLAIR scans themselves can be very variable across sites. If it is looking like it is hurting your results, then just run without it.
On 3/12/2021 11:07 AM, Xiaojiang Yang wrote:
????????External Email - Use Caution
Dear FS developers,
I have run FS?s recon-all on many cases, with and without -FLAIR options. I found the pial? surface results (?h.pial) I obtained without -FLAIR option fit to the original image (subjected/mri/orig.mgz) much better than those with -FLAIR option, at least from my visual judgment. See *MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be* https://secure-web.cisco.com/1kdfPWDTAquCY3qAKfDNtc8TRiBI5hNHL96VYA9_mTvUn4q... https://secure-web.cisco.com/1jL9MUfd9oLXR_SVyZl8-wPztrX70T9SJxxJaJElRv5e-Dj4sp4RQ3M4KUFAgUKpZxTsy39_ZpJl8bnnPbnvx2YzJvRH_uTKNfjANjJd-5gjcRF6xLXUfsXjqCmSKGe2yz1c7u_wmpF_bHrEno5pHCvh7SC8bm74VtmPYYNj-YuJSnlcZ85bx_0q82bTlL56VDSPkTK1ifobJsYiFQf7k5pSOsiAvHKbOmRIQvzx-ezp9lvzhHLbD0MIodNOc9hyrNxaG0ZWxK49VfLdGXKCgmg/https%3A%2F%2Fimgur.com%2Fa%2FwrY0HTY?for one example.
I know -FLAIR option was introduced to improve the quality of pial surface segmentation. Now for many cases, my intuition is that -FLAIR option decreases the pial quality. My questions are:
- Is this intuition correct?
- Should I trust the pial surface that?s obtained with or without -FLAIR option in general?
In addition, when I use the -FLAIR option, I sometimes get failed when running recon-all. After I did some manual edits to the brainmask image, and re-run the recon-all:
recon-all -autorecon-pial -subjid <subjectID>
I can get recon-all successful. But if I run recon-all without -FLAIR option, I can get successful results without needing to manually edit the brainmask image.
So my last question is:
- Should I just run recon-all without -FLAIR option, or, with -FLAIR option + manual edit + re-run with -autorecon-pial? Which is better?
Thank you very much!
John
On 3/22/2021 2:56 PM, Jones, Richard wrote:
External Email - Use CautionA couple of questions:-
- Do you experience similar variability with the T2 and FLAIR options or is FLAIR more variable due to it's generally lower SNR?
I have not run it enough to really say. I would think that both would do a pretty good job. FLAIR is a little more predictable because both vessels and CSF are dark.
- Should the spatial resolution of the T2/FLAIR scan match that of the T1 scan?
Yes. And they should be bandwidth matched if possible so that there is not differential distortion between them.
Richard
Message: 8 Date: Wed, 17 Mar 2021 17:51:51 -0400 From: "Douglas N. Greve" dgreve@mgh.harvard.edu Subject: Re: [Freesurfer] Which pial surface to trust, with or without -FLAIR option To: freesurfer@nmr.mgh.harvard.edu Message-ID: 3c789103-dad7-974a-0d76-58a02cba2992@mgh.harvard.edu Content-Type: text/plain; charset="utf-8"
We get a lot of variable results with FLAIR. Sometimes it helps, sometimes it hurts. FLAIR scans themselves can be very variable across sites. If it is looking like it is hurting your results, then just run without it.
On 3/12/2021 11:07 AM, Xiaojiang Yang wrote:
????????External Email - Use Caution
Dear FS developers,
I have run FS?s recon-all on many cases, with and without -FLAIR options. I found the pial? surface results (?h.pial) I obtained without -FLAIR option fit to the original image (subjected/mri/orig.mgz) much better than those with -FLAIR option, at least from my visual judgment. See *MailScanner has detected a possible fraud attempt from "secure-web.cisco.com" claiming to be* https://secure-web.cisco.com/1kdfPWDTAquCY3qAKfDNtc8TRiBI5hNHL96VYA9_mTvUn4q... https://secure-web.cisco.com/1jL9MUfd9oLXR_SVyZl8-wPztrX70T9SJxxJaJElRv5e-Dj4sp4RQ3M4KUFAgUKpZxTsy39_ZpJl8bnnPbnvx2YzJvRH_uTKNfjANjJd-5gjcRF6xLXUfsXjqCmSKGe2yz1c7u_wmpF_bHrEno5pHCvh7SC8bm74VtmPYYNj-YuJSnlcZ85bx_0q82bTlL56VDSPkTK1ifobJsYiFQf7k5pSOsiAvHKbOmRIQvzx-ezp9lvzhHLbD0MIodNOc9hyrNxaG0ZWxK49VfLdGXKCgmg/https%3A%2F%2Fimgur.com%2Fa%2FwrY0HTY?for one example.
I know -FLAIR option was introduced to improve the quality of pial surface segmentation. Now for many cases, my intuition is that -FLAIR option decreases the pial quality. My questions are:
- Is this intuition correct?
- Should I trust the pial surface that?s obtained with or without -FLAIR option in general?
In addition, when I use the -FLAIR option, I sometimes get failed when running recon-all. After I did some manual edits to the brainmask image, and re-run the recon-all:
recon-all -autorecon-pial -subjid <subjectID>
I can get recon-all successful. But if I run recon-all without -FLAIR option, I can get successful results without needing to manually edit the brainmask image.
So my last question is:
- Should I just run recon-all without -FLAIR option, or, with -FLAIR option + manual edit + re-run with -autorecon-pial? Which is better?
Thank you very much!
John
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Douglas N. Greve -
Jones, Richard