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Hello,

I am running an analysis of hippocampus volume on a set of T1-weighted scans with 1mm^3 isotropic resolution. Due to flow and other artifacts, a moderate degree of manual editing was required to correct the boundaries of each subject's hippocampus.

Final volumes of manually edited hippocampi were submitted to a repeated measures ANOVA which showed a significant main effect of diagnosis on the overall size of this structure (controlling for age and TBV).

We recently submitted this paper and just received a request from a reviewer that asked that we run a subfield analysis on these data to better understand the regions driving this overall effect.

What I'd like to know is: would the subfield approach *not* be recommended on this dataset considering that artifacts necessitated a good deal of manual intervention for the entire region? Second, if it a subfield approach *is* okay to run on these data, how can I feed in my manually edited volumes to ensure that the corrected segmentations of the entire hippocampus is used during subfield creation?

thanks very much in advance! Lara

Lara Foland-Ross, Ph.D. Research Associate and Imaging Lab Manager Center for Interdisciplinary Brain Sciences Research Stanford University School of Medicine 401 Quarry Road, Room 1356 Stanford, CA 94305-5795