title: Technical issues in the determination of cerebrovascular reserve in elderly subjects using 15O-water PET imaging.
abstract: The accurate determination of cerebrovascular reserve (CVR), especially in elderly subjects, entails several technical issues. From a review of the literature, the optimal technique employs quantitative 15O-water PET imaging determinations of cerebral blood flow (CBF) and acetazolamide (ACZ) (1 g iv with measurements at 10- to 20-min post-administration) as the vasodilating agent. CBF and CVR measurements were made using this methodology on 12 elderly subjects (3 males, 9 females, 66-84 years of age) meeting criteria for mild cognitive impairment (MCI) without other significant medical problems. Applying this quantitative technique, the cognitive and emotional status of the subject during the imaging procedure influenced the magnitude of the measurements. The semiquantitative measures resulted in even more pronounced subject state influences. The conditions under which CBF or CVR measurements are made should be controlled and reported. If semiquantitative techniques (e.g., single-photon emission-computed tomography [SPECT] imaging) must be employed for the determination of CVR, the validity of any measurement is dependent on the careful control of the general physiological status (e.g., heart rate, blood pressure, level of anxiety) of the patient.
authors.affiliation: Positron Emission Tomography Imaging Center, Department of Radiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA. laura-ponto@uiowa.edu
authors.forename: Laura L
authors.initials: LL
authors.lastname: Boles Ponto
authors.forename: Susan K
authors.initials: SK
authors.lastname: Schultz
authors.forename: G
authors.initials: G
authors.lastname: Leonard Watkins
authors.forename: Richard D
authors.initials: RD
authors.lastname: Hichwa
mesh_terms: D000086:Acetazolamide; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D001288:Attention / Q000187:drug effects / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging; D000077265:Donepezil; D005260:Female; D006801:Humans; D007189:Indans / Q000627:therapeutic use; D008297:Male; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology; D018697:Nootropic Agents / Q000627:therapeutic use; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology*; D010104:Oxygen Radioisotopes; D010880:Piperidines / Q000627:therapeutic use; D012016:Reference Values; D014055:Tomography, Emission-Computed; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014706:Verbal Learning / Q000187:drug effects / Q000502:physiology
chemical_list: D007189:Indans; D018697:Nootropic Agents; D010104:Oxygen Radioisotopes; D010880:Piperidines; D000077265:Donepezil; D000086:Acetazolamide