Hi Panos,
Then I would say that it's interesting to understand why the results change depending on the correction. Here is a list of papers that may be relevant, but you'll certainly find many others: http://www.ncbi.nlm.nih.gov/pubmed/8159014 http://pages.jh.edu/~kechen/pnas-brains.pdf http://www.touchophthalmology.com/sites/www.touchoncology.com/files/migrated...
Best,
Marie
On Jul 10, 2014, at 11:50 AM, pfotiad@nmr.mgh.harvard.edu wrote:
Hi Marie,
Thank you for your reply. I wanted to compare the LGI and Surface Area between two cohorts, from which one has a significantly higher intracranial volume than the other. I was wondering about the correction because the results, especially in the case of SA, are the opposite before and after correcting for total intraranial volume, and for LGI, it just removed the significance of the association.
Thanks again, Panos
Hi Panos,
It all depends on what your question is: whether the between-group difference in LGI and surface area is an absolute difference (then don't correct), or whether you want to see if it holds after correction. In any case, by geometric definition, the relationship between surface area, and thus LGI, and volume is governed by a power law, which means that if you linearly correct for intracranial volume, some of its effect will remain.
Hope it helps,
Marie
On Jul 10, 2014, at 10:57 AM, pfotiad@nmr.mgh.harvard.edu wrote:
Hi FS Community,
I was wondering whether LGI and Surface Area need to be corrected for total Intracranial Volume.
Thanks in advance, Panos _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
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