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Hi there,
My question is related to FreeSurfer’s calculations for intracranial volume (ICV): Given the importance to consider ICV as a potential covariate when assessing volumetric differences in ROIs between groups, which ICV output is recommended?
FreeSurfer’s recon-all generates eTIV (which is widely used by default in literature, and is a registration-based method). Conversely, the SAMSEG pipeline generates sbTIV (relatively newer approach which is a segmentation-based method). While these two would be the most obvious choice, many papers also consider correcting for supratentorial volume to be an appropriate approach.
To some degree, the choice of method would be guided by the research question. However in the most simple of cases (e.g., non-clinical cohorts), what method is recommended? Why would someone, for example, opt to use sbTIV over eTIV?
Warm regards, Jackson Lee