Understanding FreeSurfer's Cortical Thickness Measurement Process

[Steven]

Hi @rohitos,

You might find the following useful:
(FS thickness paper):
https://www.pnas.org/doi/abs/10.1073/pnas.200033797
(Another freesurfer paper):

FreeSurfer

Cortical Thickness measures using different ways of processing

FreeSurfer’s calculation of thickness is not the expected, simpler distance between white matter and pial surfaces; it’s actually a little more complicated. First, the computation is done between the smoothwm surface, not the default white matter surface, and the pial surface. For every corresponding node, the shortest distance of that node to any other node on the other surface is found. Those shortest distances from pial to smoothwm and from smoothwm to pial are then averaged to compute the th…

Best,
Steven