title: Validation of a New Imaging Technique Using the Glucose Metabolism to Amyloid Deposition Ratio in the Diagnosis of Alzheimer's Disease.
abstract: Alzheimer' disease (AD) is characterized by increase of cortical amyloid deposition in prodromal stage and subsequent decrease of cerebral glucose metabolism as disease progresses. The present study introduces the voxel-wise metabolism to amyloid deposits ratio (MAR) image and to evaluate its reliability for the diagnosis of AD.
  
  
  
  Consecutive one-hundred and forty-three subjects with AD and 181 normal subjects who underwent both 18F-FDG PET and 18F-florbetapir (AV-45) PET at baseline were included to this study from the database of Alzheimer's disease neuroimaging initiative (ADNI). After normalizing to a standard stereotactic space, the MAR image was created by dividing each FDG-PET image by corresponding AV-45 PET image using with voxel-wise inter-image computation. We examined voxel wise comparison in the MAR images between AD subjects and normal subjects and compared the diagnostic performances between the MAR image and FDG-PET and AV-45 image.
  
  
  
  In the voxel wise comparison, the MAR images of AD subjects exhibited severe and extensive decrease compared with normal subjects in the affected region in both FDG-PET and AV-45, especially in the precuneus /posterior cingulate. The highest t-value was equivalent to FDG-PET and the voxel extent was much greater than the other images. In the ROI analysis, the diagnostic accuracies were 82.6% (sensitivity: 86.7%, specificity: 79.5%), 80.7% (sensitivity: 77%, specificity: 83.4%), and 78.8% (sensitivity: 75.2%, specificity: 81.5%) for the MAR image, FDG-PET, and AV-45, respectively. AUC for the MAR image was 0.904 (95%CI: 0.867-0.942), and was larger than those for FDG-PET (AUC: 0.884, 95%CI: 0.843-0.926), and AV-45 (AUC: 0.847, 95%CI: 0.798-0.897).
  
  
  
  MAR image reflected not only amyloid deposition but the cerebral glucose metabolisms and successfully classified the subjects with AD. These data suggest that the MAR image might be a more proper appropriate diagnostic marker for AD reflecting cerebral metabolisms and amyloid deposition.
authors.affiliation: Department of Neurology, Hyogo Prefectural Rehabilitation Hospital at Nishi-Harima, Kohto 1-7-1, Shingu-cho, Tatsuno, Hyogo 679-5165, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Takahashi
authors.forename: Kazunari
authors.initials: K
authors.lastname: Ishii
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yokoyama
authors.forename: EmptyYN Y
authors.initials: EY
authors.lastname: For The Alzheimer S Disease Neuroimaging Initiative
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000145:classification / Q000000981:diagnostic imaging* / Q000378:metabolism*; D000682:Amyloid / Q000378:metabolism*; D000814:Aniline Compounds; D019540:Area Under Curve; D016208:Databases, Factual; D005026:Ethylene Glycols; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D012372:ROC Curve; D019275:Radiopharmaceuticals
chemical_list: D000682:Amyloid; D000814:Aniline Compounds; D005026:Ethylene Glycols; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C545186:florbetapir; D005947:Glucose