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Hi,

I’ve processed the same set of T1‐weighted scans with both FreeSurfer v7.2.0 and the newer v8.0.0. When I compare the regional stats (aseg + subfield tables), the absolute proportional differences are surprisingly large (anywhere from ~1 % up to nearly 200 %, depending on the structure).

I first noticed the issue while running ANCOVAs: with the v8 outputs, estimated total intracranial volume (eTIV) is highly significant in every model, whereas the v7 results (using identical R code and covariates) show a very different pattern.

I am wondering:

Are these version‐to‐version shifts expected, given the changes in v8?
Have others reported similar magnitude differences, particularly for eTIV and subcortical/hippocampal measures?
Are large shifts expected from run-to-run as well?

Any insight would be greatly appreciated, as I am concerned by the magnitude of the differences I am seeing between versions, which are significantly changing my results.

Thanks for your time.

Kindest,

Hana

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