title: Comparison of imaging biomarkers for Alzheimer's disease: amyloid imaging with [18F]florbetapir positron emission tomography and magnetic resonance imaging voxel-based analysis for entorhinal cortex atrophy.
abstract: OBJECTIVE
  We compared amyloid positron emission tomography (PET) and magnetic resonance imaging (MRI) in subjects clinically diagnosed with Alzheimer's disease (AD), mild cognitive impairment (MCI), and older healthy controls (OHC) in order to test how these imaging biomarkers represent cognitive decline in AD.
  
  
  METHODS
  Fifteen OHC, 19 patients with MCI, and 19 patients with AD were examined by [(18)F]florbetapir PET to quantify the standard uptake value ratio (SUVR) as the degree of amyloid accumulation, by MRI and the voxel-based specific regional analysis system for AD to calculate z-score as the degree of entorhinal cortex atrophy, and by mini-mental state examination (MMSE) and Alzheimer's Disease Assessment Scale-cognitive component--Japanese version (ADAS-Jcog) for cognitive functions.
  
  
  RESULTS
  Both cutoff values for measuring AD-like levels of amyloid (1.099 for SUVR) and entorhinal cortex atrophy (1.60 for z-score) were well differentially diagnosed and clinically defined AD from OHC (84.2% for SUVR and 86.7% for z-score). Subgroup analysis based on beta-amyloid positivity revealed that z-score significantly correlated with MMSE (r = -0.626, p < 0.01) and ADAS-Jcog (r = 0.691, p < 0.01) only among subjects with beta-amyloid.
  
  
  CONCLUSIONS
  This is the first study to compare [(18)F]florbetapir PET and MRI voxel-based analysis of entorhinal cortex atrophy for AD. Both [(18)F]florbetapir PET and MRI detected changes in AD compared with OHC. Considering that entorhinal cortex atrophy correlated well with cognitive decline only among subjects with beta-amyloid, [18F]florbetapir PET makes it possible to detect AD pathology in the early stage, whereas MRI morphometry for subjects with beta-amyloid provides a good biomarker to assess the severity of AD in the later stage.
authors.affiliation: Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan.
authors.forename: Amane
authors.initials: A
authors.lastname: Tateno
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sakayori
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kawashima
authors.forename: Makoto
authors.initials: M
authors.lastname: Higuchi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Suhara
authors.forename: Sunao
authors.initials: S
authors.lastname: Mizumura
authors.forename: Mark A
authors.initials: MA
authors.lastname: Mintun
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Skovronsky
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Honjo
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishihara
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kumita
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Okubo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000523:psychology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds / Q000378:metabolism; D001284:Atrophy / Q000473:pathology*; D015415:Biomarkers / Q000378:metabolism; D010054:Brief Psychiatric Rating Scale; D016022:Case-Control Studies; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D018728:Entorhinal Cortex / Q000473:pathology*; D005026:Ethylene Glycols / Q000378:metabolism; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*
chemical_list: D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D015415:Biomarkers; D005026:Ethylene Glycols; C545186:florbetapir
keywords: Alzheimer's disease; beta-amyloid; brain atrophy; cognitive function; positron emission tomography