title: Spatial nonuniformity of the resting CBF and BOLD responses to sevoflurane: in vivo study of normal human subjects with magnetic resonance imaging.
abstract: Pulsed arterial spin labeling magnetic resonance imaging (MRI) was performed to investigate the local coupling between resting regional cerebral blood flow (rCBF) and BOLD (blood oxygen level dependent) signal changes in 22 normal human subjects during the administration of 0.25 MAC (minimum alveolar concentration) sevoflurane. Two states were compared with subjects at rest: anesthesia and no-anesthesia. Regions of both significantly increased and decreased resting-state rCBF were observed. Increases were limited primarily to subcortical structures and insula, whereas, decreases were observed primarily in neocortical regions. No significant change was found in global CBF (gCBF). By simultaneously measuring rCBF and BOLD, region-specific anesthetic effects on the coupling between rCBF and BOLD were identified. Multiple comparisons of the agent-induced rCBF and BOLD changes demonstrated significant (P < 0.05) spatial variability in rCBF-BOLD coupling. The slope of the linear regression line for AC, where rCBF was increased by sevoflurane, was markedly smaller than the slope for those ROIs where rCBF was decreased by sevoflurane, indicating a bigger change in BOLD per unit change in rCBF in regions where rCBF was increased by sevoflurane. These results suggest that it would be inaccurate to use a global quantitative model to describe coupling across all brain regions and in all anesthesia conditions. The observed spatial nonuniformity of rCBF and BOLD signal changes suggests that any interpretation of BOLD fMRI data in the presence of an anesthetic requires consideration of these insights.
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, The Anlyan Center N128, New Haven, Connecticut 06520-8042, USA. maolin.qiu@yale.edu
authors.forename: Maolin
authors.initials: M
authors.lastname: Qiu
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Ramani
authors.forename: Michael
authors.initials: M
authors.lastname: Swetye
authors.forename: Robert Todd
authors.initials: RT
authors.lastname: Constable
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001921:Brain / Q000098:blood supply / Q000187:drug effects* / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D002536:Cerebral Arteries / Q000187:drug effects / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects* / Q000502:physiology; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008738:Methyl Ethers / Q000494:pharmacology*; D008959:Models, Neurological; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D012016:Reference Values; D012044:Regression Analysis; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane