Hi Vy,
no, it shouldn't. The pial surfaces are not trustworthy near the hippocampus, and we don't use them there.
Bruce On Wed, 28 Sep 2011, Vy Dinh wrote:
Dear Experts, I noticed that the inferior horn of the lateral ventricles are not included within the pial surface while the posterior lateral ventricles are and wonder how one should go about when making corrections for the pial surface. This was observed in the subjects that I have worked with and also with the Freesurfer tutorial sample data. For the sample data, it appears that the hippocampus provides a clear delineation of the inferior and posterior lateral ventricles in the sagittal view (see attached image "bert") which was not observed with our subjects (see attached images "sub"). The segmentation of the lateral ventricles, however, looks correct (by using the segmentation label function), so I am unsure if this discrepancy affects the measurements at all. However, it is worth confirming. I look forward to reading your responses.
Thank you very much,
Vy T.U. Dinh Research Assistant, Neurological Sciences Rush University Medical Center Phone: (312) 563-3853 Fax: (312) 563-4660 Email: Vy_dinh@rush.edu