title: Relationship of Hippocampal Volume to Amyloid Burden across Diagnostic Stages of Alzheimer's Disease.
abstract: OBJECTIVE
  To assess how hippocampal volume (HV) from volumetric magnetic resonance imaging (vMRI) is related to the amyloid status at different stages of Alzheimer's disease (AD) and its relevance to patient care.
  
  
  METHODS
  We evaluated the ability of HV to predict the florbetapir positron emission tomography (PET) amyloid positive/negative status by group in healthy controls (HC, n = 170) and early/late mild cognitive impairment (EMCI, n = 252; LMCI, n = 136), and AD dementia (n = 75) subjects from the Alzheimer's Disease Neuroimaging Initiative Grand Opportunity (ADNI-GO) and ADNI2. Logistic regression analyses, including elastic net classification modeling with 10-fold cross-validation, were used with age and education as covariates.
  
  
  RESULTS
  HV predicted amyloid status only in LMCI using either logistic regression [area under the curve (AUC) = 0.71, p < 0.001] or elastic net classification modeling [positive predictive value (PPV) = 72.7%]. In EMCI, age (AUC = 0.70, p < 0.0001) and age and/or education (PPV = 63.1%), but not HV, predicted amyloid status.
  
  
  CONCLUSIONS
  Using clinical neuroimaging, HV predicted amyloid status only in LMCI, suggesting that HV is not a biomarker surrogate for amyloid PET in clinical applications across the full diagnostic spectrum.
authors.affiliation: Indiana University School of Medicine, Indianapolis, Ind., USA.
authors.forename: Paula T
authors.initials: PT
authors.lastname: Trzepacz
authors.forename: Helen
authors.initials: H
authors.lastname: Hochstetler
authors.forename: Peng
authors.initials: P
authors.lastname: Yu
authors.forename: Peter
authors.initials: P
authors.lastname: Castelluccio
authors.forename: Michael M
authors.initials: MM
authors.lastname: Witte
authors.forename: Grazia
authors.initials: G
authors.lastname: Dell'Agnello
authors.forename: Elisabeth K
authors.initials: EK
authors.lastname: Degenhardt
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D000682:Amyloid / Q000032:analysis*; D016229:Amyloid beta-Peptides / Q000032:analysis*; D000814:Aniline Compounds; D001284:Atrophy; D015415:Biomarkers / Q000032:analysis; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D018450:Disease Progression; D005026:Ethylene Glycols; D005260:Female; D006624:Hippocampus / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D009929:Organ Size; D049268:Positron-Emission Tomography
chemical_list: D000682:Amyloid; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D015415:Biomarkers; D005026:Ethylene Glycols; C545186:florbetapir