Hi Sam usually this means that the cerebellum is too far from isocenter and hence has low SNR/more distortion. If you can place your subjects higher in the scanner that might help.
For existing data try putting some control points in cerebellar wm or brainstem. That might help cheers Bruce On Mon, 1 Aug 2016, Sam Mathias wrote: > Dear list, > I'm interested in measuring cerebellar volumes using freesurfer. However, > the automatic segmentation (aseg) seems to be doing a poor job of capturing > the whole structure for many subjects. Specifically, it is chopping off the > bottom of the cerebellum. Here is an example: > > https://drive.google.com/open?id=0B68CY3v4cg7tS0hSNkVVMWNiZV8xYWR2eTJQQlhFe > VM0Q2Jn > > The issue seems to be when the cerebellum is very close to the bottom of the > image, as is the case in many of our scans. Has anyone encountered similar > issues with cerebellum segmentation, and if so, have any advice about how to > improve it? > > Many thanks, > > -- > Samuel R. Mathias, Ph.D. > Associate Research Scientist (ARS) > Neurocognition, Neurocomputation and Neurogenetics (n3) Division > Yale University School of Medicine > 40 Temple Street, Room 694 > New Haven CT 06511 > http://www.srmathias.com > > _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
