Hi folks,
I have been puzzled for a while with the results from couple of my subjects. They all have clearly visible cerebral atrophy (says neuroradiologist). I ran them through FS-4.0.1 and aseg.stat gives me, as expected, severe loss of gray matter (and others as well) as follows:
GM ICV normalized Age matched reference ICV normalized
What's puzzling me is the cortical thickness. Except of few locations, cortical thickness is within the STD of the controls, and at places it's even thicker. I am wondering, where such a huge GM volume loss (aseg.stats) comes from? Very simplified explanation could be that there is ^3 relation between volume and one of the dimensions of a structure ( V ~ x^3 ). In that case, it would be more sensitive to look at the volume of a parcelated cortical GM. But then, the intersubject variability of the cortical area would come into the play. Is there any other explanation? Is there a single parameter assessing cortical atrophy?
Thanks a lot for the ideas in advance .
Martin
PS.: BTW, what is happening with the OASIS dataset analyzed using FS? When it was released the first time, there were some inconsistencies and it was pulled down from the ftp.