title: Global gray matter changes in posterior cortical atrophy: a serial imaging study.
abstract: BACKGROUND
  Posterior cortical atrophy (PCA) is a neurodegenerative condition predominantly associated with Alzheimer's disease (AD) pathology. Cross-sectional imaging studies have shown different atrophy patterns in PCA patients compared with typical amnestic Alzheimer's disease (tAD) patients, with greatest atrophy commonly found in posterior regions in the PCA group, whereas in the tAD group, atrophy is most prominent in medial temporal lobe regions. However, differential longitudinal atrophy patterns are not well understood.
  
  
  METHODS
  This study assessed longitudinal changes in brain and gray matter volumes in 17 PCA patients, 16 tAD patients, and 18 healthy control subjects. Both patient groups had symptom durations of approximately 5 years.
  
  
  RESULTS
  Progressive gray matter losses in both PCA and tAD patients were relatively widespread throughout the cortex, compared with control subjects, and were not confined to areas related to initial symptomatology. A multivariate classification analysis revealed a statistically significant group separation between PCA and tAD patients, with 72.7% accuracy (P < .01).
  
  
  CONCLUSIONS
  Progression from an initially focal presentation to a more global pattern suggests that these different clinical presentations of AD might converge pathologically over time.
authors.affiliation: Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK. lehmann@drc.ion.ucl.ac.uk
authors.forename: Manja
authors.initials: M
authors.lastname: Lehmann
authors.forename: Josephine
authors.initials: J
authors.lastname: Barnes
authors.forename: Gerard R
authors.initials: GR
authors.lastname: Ridgway
authors.forename: Natalie S
authors.initials: NS
authors.lastname: Ryan
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Warrington
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Crutch
authors.forename: Nick C
authors.initials: NC
authors.lastname: Fox
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000473:pathology*; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000473:pathology*; D009483:Neuropsychological Tests; D060388:Support Vector Machine