title: Day-to-day test-retest variability of CBF, CMRO2, and OEF measurements using dynamic 15O PET studies.
abstract: OBJECTIVE
  We assessed test-retest variability of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rate of oxygen (CMRO(2)), and oxygen extraction fraction (OEF) measurements derived from dynamic (15)O positron emission tomography (PET) scans.
  
  
  METHODS
  In seven healthy volunteers, complete test-retest (15)O PET studies were obtained; test-retest variability and left-to-right ratios of CBF, CBV, OEF, and CMRO(2) in arterial flow territories were calculated.
  
  
  RESULTS
  Whole-brain test-retest coefficients of variation for CBF, CBV, CMRO(2), and OEF were 8.8%, 13.8%, 5.3%, and 9.3%, respectively. Test-retest variability of CBV left-to-right ratios was <7.4% across all territories. Corresponding values for CBF, CMRO(2), and OEF were better, i.e., <4.5%, <4.0%, and <1.4%, respectively.
  
  
  CONCLUSIONS
  The test-retest variability of CMRO(2) measurements derived from dynamic (15)O PET scans is comparable to within-session test-retest variability derived from steady-state (15)O PET scans. Excellent regional test-retest variability was observed for CBF, CMRO(2), and OEF. Variability of absolute CBF and OEF measurements is probably affected by physiological day-to-day variability of CBF.
authors.affiliation: Department of Neurosurgery, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Jochem P
authors.initials: JP
authors.lastname: Bremmer
authors.forename: Bart N M
authors.initials: BN
authors.lastname: van Berckel
authors.forename: Suzanne
authors.initials: S
authors.lastname: Persoon
authors.forename: L Jaap
authors.initials: LJ
authors.lastname: Kappelle
authors.forename: Adriaan A
authors.initials: AA
authors.lastname: Lammertsma
authors.forename: Reina
authors.initials: R
authors.lastname: Kloet
authors.forename: Gert
authors.initials: G
authors.lastname: Luurtsema
authors.forename: Abraham
authors.initials: A
authors.lastname: Rijbroek
authors.forename: Catharina J M
authors.initials: CJ
authors.lastname: Klijn
authors.forename: Ronald
authors.initials: R
authors.lastname: Boellaard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology*; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000473:pathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D010104:Oxygen Radioisotopes; D010100:Oxygen