[Freesurfer] ventricles labeled as white matter in hydrocephalus brain

I am trying to use FreeSurfer to measure ventricular volume among patients with normal pressure hydrocephalus. I have run the first subject, whose ventricles are huge. When looking at the subcortical segmentation (aseg.mgz) in tkmedit, I saw that large portions of the ventricles are labeled as cerebral white matter or white matter hypointensities. I tried filling in the ventricles in the wm.mgz volume and then running autorecon2-wm, but this does not appear to have changed anything in the aseg.mgz segmentation nor in the aseg.stats file. Is there a way I can correct this problem, and/or prevent it when I run more NPH patients?

Thanks, Dana

Dana W. Moore, Ph.D. Neuropsychology Fellow Cornell Neuropsychology Service Weill Medical College of Cornell University New York Presbyterian Hospital Department of Neurology & Neuroscience 428 East 72nd Street, Suite 500 New York, NY 10021 Phone: 212-746-2823 Fax: 212-746-5584 Email: dwm2003@med.cornell.edu