Just a thought, but I suspect that the volume is calculated as some product of area * "thickness". Then, with the -t option, what FS is using as thickness is now really the lgi value. So, the "volume" value is really not appropriate in that case.
cheers, Mike H.
On Fri, 2008-05-09 at 15:28 +0200, Marie Schaer wrote:
On my understanding, the GM volume given by mris_anatomical_stats should be the same independently of the -t option (unless you reprocessed the surfaces in between), so that's surprising.
Doug, do you have any idea?
Marie
On 9 mai 08, at 15:12, Martin Kavec wrote:
Thanks a lot for clarification, Marie.
On Friday 09 May 2008 14:37:46 Marie Schaer wrote:
Martin,
As lgi is read like a thickness file, the lgi values in your tabular output replaced the value where you had thickness before. So mean lgi is in column 4 (note that average lgi values per parcell are comprised between 1 and 5 if your lgi computation is ok). Standard deviation for lgi is in column 5. The other columns should not change if you run mris_anatomical_stats without the -t option (i.e on the thickness).
Well, the point is that the 3rd column (not counting the structure name) is changed as well. This corresponds to GM volume, which is (almost) systematically larger in the lh.lgi.stats. Should it really be the same? This is already off my questions, but I am just saying that as a feedback.
Thanks a lot,
Martin
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