title: Relationship between Alzheimer disease-like pattern of 18F-FDG and fasting plasma glucose levels in cognitively normal volunteers.
abstract: Increased plasma glucose (PG) levels can alter the cerebral distribution pattern of (18)F-FDG uptake and reduce (18)F-FDG uptake, especially in the precuneus. The (18)F-FDG distribution pattern in cognitively normal subjects is described as an Alzheimer disease (AD)-like pattern. The aim of this study was to determine the fasting PG levels that can reduce (18)F-FDG uptake in the precuneus.
  
  
  METHODS
  Fifty-one cognitively normal volunteers (mean age ± SD, 69.7 ± 5.9 y) underwent (18)F-FDG PET scanning and were divided into 2 groups according to the level of fasting PG at the time of PET scanning: control (n = 31, 80 mg/dL ≤ fasting PG < 100 mg/dL) and impaired fasting glucose (IFG) (n = 20, 100 mg/dL ≤ fasting PG < 110 mg/dL). (18)F-FDG uptake was compared between the 2 groups using voxelwise analyses with a global normalization method and volume-of-interest (VOI)-based analyses. VOIs were placed on the precuneus, posterior cingulate, and visual cortex, and the ratio of the uptake value on the precuneus VOI to that on the visual cortex VOI (PreCne/VC ratios) and to that on the posterior cingulate VOI (PreCne/PostCin ratios) was calculated.
  
  
  RESULTS
  Whole-brain voxelwise analyses showed that (18)F-FDG uptake in the precuneus was significantly lower in the IFG group (P < 0.05, familywise error rate-corrected) than in the control group. VOI analyses showed significantly lower PreCne/VC ratios (P = 0.002) and PreCne/PostCin ratios (P = 0.004) in the IFG group than in the control group.
  
  
  CONCLUSIONS
  The present study confirmed that increased fasting PG levels decrease (18)F-FDG uptake, especially in the precuneus, as in the AD-like pattern. Furthermore, the study provided initial evidence that the AD-like pattern can appear even in an individual with a mildly higher level of fasting PG (100-110 mg/dL).
authors.affiliation: Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan; and ishibashi@pet.tmig.or.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishibashi
authors.affiliation: Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan; and.
authors.forename: Airin
authors.initials: A
authors.lastname: Onishi
authors.affiliation: Research Team for Social Participation and Community Health, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan; and.
authors.forename: Kiichi
authors.initials: K
authors.lastname: Ishiwata
authors.affiliation: Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan; and.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishii
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D001786:Blood Glucose / Q000032:analysis*; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D003071:Cognition; D005260:Female; D019788:Fluorodeoxyglucose F18; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals
chemical_list: D001786:Blood Glucose; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Alzheimer’s disease; FDG; PET; precuneus, glucose