Hello, I want to measure the volume of my groups' cortex, n=139, mostly males. I am using fs 3.0.5.
From the aseg.stats file, lh + rh white matter is 548,000 and gray matter is
487,000, for a ratio of 1.1. I know the aseg.stats file is not a good place to go for gray matter volume, as it is usually underestimated.
Looking in the aparc.a2005.stats file, the average white matter is 606,000 and gray matter is 463,000, for a ratio of 1.3.
I was surprised the gray matter actually went down, and the ratio of 1.3 seems a bit high. Is this normal? I see in the aseg.stats file, skin left over after the watershed is counted as cortex and so is a fair amount around the cerebellum. Could partial volumeing also be a possible explanation? I would think that the aparc file would be most accurate, but with these results, I wanted to doublecheck.
Thanks Bruce for answering my earlier question. I am still looking at the pallidum differences and will let you know soon.
Thanks! Jeff Sadino