title: Comparison of methods for measuring longitudinal brain change in cognitive impairment and dementia.
abstract: OBJECTIVE
  The goal of this project was to compare MRI measures of hippocampal, entorhinal cortex (ERC), and whole brain longitudinal change in cognitively normal elderly controls (C), non-demented subjects with cognitive impairment (CI), and demented (D) subjects.
  
  
  METHODS
  16 C, 6 CI, and 7 D subjects of comparable age were studied with MRI twice, at least 1 year apart. Longitudinal change in total brain size was measured by several methods, including computerized segmentation, non-linear warping, and change in the fluid/tissue boundaries between cerebrospinal fluid (CSF) and brain. Change in hippocampal volume was measured by semi-automated methods, and ERC volumes were manually measured.
  
  
  RESULTS
  The annual rate of atrophy was greater in D versus C and D versus CI for cortical gray matter (cGM) (P=0.009 and 0.002), hippocampus (P=0.0001 and 0.002), and for the change in the fluid/tissue boundary (P=0.03 and 0.03). The annual rate of atrophy of ERC was greater in both CI and D versus C (P=0.01 and 0.0002). No significant differences between groups were found using non-linear warping.
  
  
  CONCLUSIONS
  In CI, the greatest annual rates of atrophy were in ERC, while in D the greatest annual rates of atrophy were in hippocampus and cortex. Progressive ERC atrophy was observed with a greater degree of cognitive impairment, while hippocampal and cortical atrophy were only observed in demented subjects.
authors.affiliation: Department of Veterans Affairs Medical Center, Magnetic Resonance Unit, 4150 Clement Street (116R), San Francisco, CA 94121, USA. valerie@itsa.ucsf.edu
authors.forename: V A
authors.initials: VA
authors.lastname: Cardenas
authors.forename: A T
authors.initials: AT
authors.lastname: Du
authors.forename: D
authors.initials: D
authors.lastname: Hardin
authors.forename: F
authors.initials: F
authors.lastname: Ezekiel
authors.forename: P
authors.initials: P
authors.lastname: Weber
authors.forename: W J
authors.initials: WJ
authors.lastname: Jagust
authors.forename: H C
authors.initials: HC
authors.lastname: Chui
authors.forename: N
authors.initials: N
authors.lastname: Schuff
authors.forename: M W
authors.initials: MW
authors.lastname: Weiner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000473:pathology*; D003704:Dementia / Q000473:pathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018709:Statistics, Nonparametric