Hi Julia

I’m not sure what a group-level dice map would be. Maybe you are talking about an accuracy map? Like how often a single point is in one label vs. another? For individual cortical labels you can generate this for each label across subjects using mris_spherical_average. If you really mean Dice it won’t give you a map – it gives you 1 number per pair of subjects per label. You can certainly compute that for each pair, or to some target, then compute the mean and variance of that

Cheers
Bruce

From: freesurfer-bounces@nmr.mgh.harvard.edu <freesurfer-bounces@nmr.mgh.harvard.edu> On Behalf Of Hye Min Shin
Sent: Wednesday, June 23, 2021 10:00 AM
To: freesurfer@nmr.mgh.harvard.edu
Subject: [Freesurfer] Calculating group-wise Dice Similarity Coefficient and corresponding surface map

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Hello experts,

I apologize if this has been asked before- but I couldn't find a question that was similar to what I wanted to know about so I decided to ask this question(s). 

I am trying to calculate dice similarity coefficient (DSC) for a group of subjects and I was wondering if it is possible to calculate this on FreeSurfer. 

I understand that FreeSurfer has mri_compute_overlap that can compute dice coefficient but I wasn't sure if this can be done on group-level. Do I have to first calculate dice for each subject and then calculate the average dice for the subjects? 

Also I was wondering if there is a way to visualize group-level dice coefficient map on inflated lh/rh surface. 

Best,

Julia Shin