Hi,
I have been running quite a few clinical subjects (close to 300) through FS pipeline and comparing cortical thickness from parcellated cortex for each individual subject to its agematched controls. The subject clinical symptoms are not specific, ranging from amnesia, reduced ability to generate words, confusion, ...
Every now and that I see that the cortical thickness is suspiciously higher than STD of the controls even if there are no leftovers after brain extraction (I specifically verify it, and if necessary do the corrections). In the vast majority of these cases I also find lower total white matter volume.
I am speculating, if possible subcortical WM disease (as detected by reduced total volume of the WM) may come into the play. If subcortical WM gets darker, near the intensity of the GM, the cortical thickness may be overestimated. Could anybody comment on this idea?
I suppose there is no way of correcting this. At the same time I wonder, whether cortical atrophy in MS assessed by the FS is accurate. The cortical atrophy reported in MS by FS methods (Sailer2003) was highly focal, and I am wondering if such atrophy can reflect the wide range of disables and clinical symptoms.
I would appreciate any comments to my thought.
Best,
Martin