Hi Prad, 

Thank you for your response! Unfortunately the problematic issue here is cortical MS lesions, which is not as easily fixed as WM lesions. If you plan on using LST (which is a nice tool indeed) be sure to be attentive to juxtacortical lesions as these, from my experience, are not always picked up as nicely using LST:s LPA algorithm and may still cause some issues. They would, however, still be editable as usual in FreeSurfer. 

Have a nice weekend! 

Kind regards,
Tobias
 
On 15 jan 2016, at 16:10, Bharadwaj, Pradyumna - (prad) <prad@email.arizona.edu> wrote:

Hello Tobias,

The lesion segmentation toolbox, which has been validated in MS patients (http://www.applied-statistics.de/lst.html) has a useful tool to fill in T1 hypointensities (based on Chard et al., 2010; http://onlinelibrary.wiley.com/doi/10.1002/jmri.22214/abstract ).

The toolbox generates lesion probability maps, which can then be used to 'fill in' the lesions, with normally appearing white matter. You could then run recon-all on these filled in T1 images. I haven't used such an approach myself, so I don't have any data regarding the validity of or accuracy of cortical measures obtained using such a method. 

Best,
Prad

From: freesurfer-bounces@nmr.mgh.harvard.edu <freesurfer-bounces@nmr.mgh.harvard.edu> on behalf of Granberg, Erik Tobias <EGRANBERG@mgh.harvard.edu>
Sent: Friday, January 15, 2016 1:15 PM
To: freesurfer@nmr.mgh.harvard.edu
Subject: [Freesurfer] Cortical MS lesions - correcting pial surfaces
 
Dear FreeSurfer colleagues,

We’re working with MS data and wanted your input on how we could best handle patients with extensive cortical pathology causing inaccurate reconstructions of the surfaces. In short the pial surfaces “dips” in too deep towards the WM surface due to the T1-hypointensity. 

A lot of the problems can be mediated by doing wm.mgz edits and actually including the lesioned tissues, which pushes out both surfaces to an accurate position. Sometimes though, the cortical lesion affects the whole depth of the surface and this trick does not help. 

Is there any way to directly push out or “anchor” the pial surface? 

Thank you for the help! 

Kind regards,
Tobias
 
Post-doctoral research fellow 
Multiple Sclerosis Imaging Group 
MGH/HMS/MIT Athinoula A. Martinos Center for Biomedical Imaging 
149 13th St Charlestown, MA 02129
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