title: Cerebral blood flow, blood volume, and oxygen metabolism dynamics in human visual and motor cortex as measured by whole-brain multi-modal magnetic resonance imaging.
abstract: The development of neuroimaging methods to characterize flow-metabolism coupling is crucial for understanding mechanisms that subserve oxygen delivery. Functional magnetic resonance imaging (fMRI) using blood-oxygenation-level-dependent (BOLD) contrast reflects composite changes in cerebral blood volume (CBV), cerebral blood flow (CBF), and the cerebral metabolic rate of oxygen consumption (CMRO(2)). However, it is difficult to separate these parameters from the composite BOLD signal, thereby hampering MR-based flow-metabolism coupling studies. Here, a novel, noninvasive CBV-weighted MRI approach (VASO-FLAIR with 3D GRASE (GRadient-And-Spin-Echo)) is used in conjunction with CBF-weighted and BOLD fMRI in healthy volunteers (n=7) performing simultaneous visual (8 Hz flashing-checkerboard) and motor (1 Hz unilateral joystick) tasks. This approach allows for CBV, CBF, and CMRO(2) to be estimated, yielding (mean+/-s.d.): DeltaCBF=63%+/-12%, DeltaCBV=17%+/-7%, and DeltaCMRO(2)=13%+/-11% in the visual cortex, and DeltaCBF=46%+/-11%, DeltaCBV=8%+/-3%, and DeltaCMRO(2)=12%+/-13% in the motor cortex. Following the visual and motor tasks, the BOLD signal became more negative (P=0.003) and persisted longer (P=0.006) in the visual cortex compared with the motor cortex, whereas CBV and CBF returned to baseline earlier and equivalently. The proposed whole-brain technique should be useful for assessing regional discrepancies in hemodynamic reactivity without the use of intravascular contrast agents.
authors: Department of Clinical Neurology, FMRIB Centre, University of Oxford, Oxford, UK. manus.donahue@clneuro.ox.ac.uk
authors: Manus J
authors: MJ
authors: Donahue
authors: Jakob U
authors: JU
authors: Blicher
authors: Leif
authors: L
authors: Østergaard
authors: David A
authors: DA
authors: Feinberg
authors: Bradley J
authors: BJ
authors: MacIntosh
authors: Karla L
authors: KL
authors: Miller
authors: Matthias
authors: M
authors: Günther
authors: Peter
authors: P
authors: Jezzard
mesh_terms: D000328:Adult; D001810:Blood Volume; D001811:Blood Volume Determination; D001921:Brain / Q000098:blood supply / Q000378:metabolism; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000008:administration & dosage; D006801:Humans; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009044:Motor Cortex / Q000098:blood supply* / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D013113:Spin Labels; D014793:Visual Cortex / Q000098:blood supply* / Q000378:metabolism
chemical_list: D003287:Contrast Media; D013113:Spin Labels; D010100:Oxygen