title: Reduced global brain metabolism but maintained vascular function in amnestic mild cognitive impairment.
abstract: Amnestic mild cognitive impairment represents an early stage of Alzheimer's disease, and characterization of physiological alterations in mild cognitive impairment is an important step toward accurate diagnosis and intervention of this condition. To investigate the extent of neurodegeneration in patients with mild cognitive impairment, whole-brain cerebral metabolic rate of oxygen in absolute units of µmol O2/min/100 g was quantified in 44 amnestic mild cognitive impairment and 28 elderly controls using a novel, non-invasive magnetic resonance imaging method. We found a 12.9% reduction ( p = 0.004) in cerebral metabolic rate of oxygen in mild cognitive impairment, which was primarily attributed to a reduction in the oxygen extraction fraction, by 10% ( p = 0.016). Global cerebral blood flow was not found to be different between groups. Another aspect of vascular function, cerebrovascular reactivity, was measured by CO2-inhalation magnetic resonance imaging and was found to be equivalent between groups. Therefore, there seems to be a global, diffuse diminishment in neural function in mild cognitive impairment, while their vascular function did not show a significant reduction.
authors.affiliation: 1 Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Binu P
authors.initials: BP
authors.lastname: Thomas
authors.affiliation: 1 Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Sheng
authors.affiliation: 2 Institute of Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.
authors.forename: Benjamin Y
authors.initials: BY
authors.lastname: Tseng
authors.affiliation: 2 Institute of Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tarumi
authors.affiliation: 3 Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Kristen
authors.initials: K
authors.lastname: Martin-Cook
authors.affiliation: 3 Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Kyle B
authors.initials: KB
authors.lastname: Womack
authors.affiliation: 3 Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.|4 Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Munro C
authors.initials: MC
authors.lastname: Cullum
authors.affiliation: 2 Institute of Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Levine
authors.affiliation: 2 Institute of Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.|3 Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: 1 Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.|5 Department of Radiology, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Hanzhang
authors.initials: H
authors.lastname: Lu
mesh_terms: D000368:Aged; D000647:Amnesia / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D010100:Oxygen
keywords: Mild cognitive impairment; cerebral metabolic rate of oxygen; cerebrovascular reactivity; elderly controls; oxygen extraction fraction