Thank you for looking into the deeper mechanics of this issue. In my case I am dealing with motion contaminated 1.5T data which require extensive and somewhat intricate edits to the white matter bleed into the pial surface, as well as into dura. In working with a past dataset of similar characteristics I was consistently impressed with fs 5.3’s ability to properly segment white matter in most cases and the robustness of the editing response. I was left with the overall impression that freesurfer handled noisy data quite well with a little bit of help. Our results from the analysis of corrected vs uncorrected data were very strong in favor of the editing protocol.
My experience with 6.0, aside from any issues of information not propagating through the longitudinal stream, is that there are many more cases in which the white matter surface will not conform to the edits suggested in the white matter volume. A number of tricks to “convince” the software in cases of non-response used in 5.3, such as making sure to complete edits on adjacent slices, are simply not effective. I am left with the overall impression that I have very little control over the white matter surfaces really, beyond making suggestions which may only slightly change the degree of error, but does not fundamentally change the structure of the white matter surface enough to remove the misclassification entirely in many cases. Best, David P. Semanek, HCISPP Research Technician, Posner Lab Division of Child and Adolescent Psychiatry Columbia University Medical Center New York State Psychiatric Institute 1051 Riverside Drive, Pardes Bldg. 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From: Antonin Skoch <a...@ikem.cz> Date: Thursday, April 20, 2017 at 10:25 AM To: David Semanek <seman...@nyspi.columbia.edu>, "freesurfer@nmr.mgh.harvard.edu" <freesurfer@nmr.mgh.harvard.edu> Subject: Re: [Freesurfer] Worse determination of ?h.white with v6.0 in comparison to v5.3 - worse GM/WM contrast Dear David, thank you for the feedback; I saw your posts concerning edits and responded to them, see http://www.mail-archive.com/freesurfer@nmr.mgh.harvard.edu/msg52549.html Just my case is not concerning poor response to the edits (which I believe is not systematically different between 5.3 and 6.0), my concern is that the data processed by v6.0 need much more wm.mgz edits than data processed by v5.3. I think that my issue lies in -normalization2 step of recon-all. One of the difference between v5.3 and v6.0 is that by default the -mprage flag is passed to mri_normalize. This affects several parameters inside mri_normalize. I tried to reprocess my subjects using v6.0 with -no-mprage, but unfortunately this did not help. See the example screenshots processed by v5.3 and v6.0 with -no-mprage: The brain.mgz is still more aggressively filtered in v6.0 and there is much more prominent leak of ?h.white outside brain, which is probably caused by extended filtration which affects GM/WM contrast. Looking at the source code of mri_normalize.c I did not comprehend where the basis of the issue lies, but in any case there are big differences in mri_normalize.c code between versions. Antonin From: David Semanek <seman...@nyspi.columbia.edu> To: Antonin Skoch <a...@ikem.cz>, "freesurfer@nmr.mgh.harvard.edu" <freesurfer@nmr.mgh.harvard.edu> Sent: 4/20/2017 3:41 PM Subject: Re: [Freesurfer] Worse determination of ?h.white with v6.0 in comparison to v5.3 - worse GM/WM contrast Agreed. A validated protocol run on a very large group of subjects in 5.3 was attempted with similar data in 6.0 and not only was the longitudinal edit stream nearly non-functional for white matter edits, cross edit performance was disappointing. I am currently waiting on a response to these potential issues before pursuing further work with 6.0. Best, David P. Semanek, HCISPP Research Technician, Posner Lab Division of Child and Adolescent Psychiatry Columbia University Medical Center New York State Psychiatric Institute 1051 Riverside Drive, Pardes Bldg. Rm. 2424 New York, NY 10032 PH: (646) 774-5885 IMPORTANT NOTICE: This e-mail is meant only for the use of the intended recipient. It may contain confidential information which is legally privileged or otherwise protected by law. If you received this e-mail in error or from someone who was not authorized to send it to you, you are strictly prohibited from reviewing, using, disseminating, distributing or copying the e-mail. PLEASE NOTIFY US IMMEDIATELY OF THE ERROR BY RETURN E-MAIL AND DELETE THIS MESSAGE FROM YOUR SYSTEM. Thank you for your cooperation. From: Antonin Skoch <a...@ikem.cz> Date: Wednesday, April 19, 2017 at 5:23 PM To: <freesurfer@nmr.mgh.harvard.edu> Subject: [Freesurfer] Worse determination of ?h.white with v6.0 in comparison to v5.3 - worse GM/WM contrast Dear experts, I am sending just one more example to illustrate issue with white surface estimation in v6.0. See the attached screenshots: In v6.0 there seems to be insufficient contrast in brain.finalsurfs.mgz, so the white surface is leaking at three spots dramatically outwards towards pial surface. The white surface in v5.3 looks much more anatomically relevant in the same spot. Could you please comment on how to avoid such issues in v.6.0? Regards, Antonin Skoch
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