title: Resting state brain glucose metabolism is not reduced in normotensive healthy men during aging, after correction for brain atrophy.
abstract: Studies using positron emission tomography (PET) have reported that global and regional values for cerebral blood flow and metabolic rates for glucose (CMRglc and rCMRglc) decline with age in humans. We wished to determine if such decreases could have reflected a partial volume effect (PVE) of cerebral atrophy in the elderly, rather than "intrinsic" reductions per gram brain. We used PET to compare rCMRglc, before and after correcting for the PVE, between 13 healthy older men (aged: 55-82 years) and 11 healthy young men (aged: 22-34 years). PET was performed with 18F-fluoro-2-deoxy-d-glucose while the subjects were in the "resting" state (eyes covered and ears plugged with cotton). The PET scans were normalized to a common brain volume after superimposing them on the subjects' tissue segmented magnetic resonance scans. Analysis showed that rCMRglc in the absence of a PVE correction was significantly less in the older group in insular, frontal, superior temporal cortical, and thalamic regions. Statistical significant differences in rCMRglc, however, were absent after the PVE correction. Thus, statistically significant age reductions in regional brain glucose metabolism, corrected for brain atrophy, are not detectable in healthy normotensive men scanned while in the resting state.
authors.affiliation: Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Vicente
authors.initials: V
authors.lastname: Ibáñez
authors.forename: Pietro
authors.initials: P
authors.lastname: Pietrini
authors.forename: Maura L
authors.initials: ML
authors.lastname: Furey
authors.forename: Gene E
authors.initials: GE
authors.lastname: Alexander
authors.forename: Philippe
authors.initials: P
authors.lastname: Millet
authors.forename: Arun L W
authors.initials: AL
authors.lastname: Bokde
authors.forename: Diane
authors.initials: D
authors.lastname: Teichberg
authors.forename: Mark B
authors.initials: MB
authors.lastname: Schapiro
authors.forename: Barry
authors.initials: B
authors.lastname: Horwitz
authors.forename: Stanley I
authors.initials: SI
authors.lastname: Rapoport
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism* / Q000473:pathology; D001284:Atrophy / Q000378:metabolism / Q000473:pathology; D001794:Blood Pressure / Q000502:physiology*; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D014055:Tomography, Emission-Computed / Q000379:methods
chemical_list: D005947:Glucose