title: The cerebral vasomotor response in varying CO(2) concentrations, as evaluated using cine phase contrast MRI: Flow, volume, and cerebrovascular resistance indices.
abstract: OBJECTIVE
  Previous studies have identified that impaired cerebral vasomotor reactivity (VMR) is associated with a higher risk of stroke and transient ischemic attack. This study aims to evaluate VMR by measuring the blood flow waveforms of the supplying arteries and dural sinuses using cine phase contrast MRI (PC MRI) and hypercapnic challenge.
  
  
  METHODS
  PC MRI flow quantification was performed on an oblique slice approximately perpendicular to the target vessels to include the left (LICA) and right internal carotid artery (RICA), basilar artery (BA), sinus rectus (SR), and superior sagittal sinus (SSS). A total of four PC MRI scans were performed at different CO(2) concentrations (room air and 3%, 5%, and 7% CO(2)).
  
  
  RESULTS
  The analyses obtained the flow parameters and cerebrovascular resistance parameters for all five vessels. Results indicated that the vascular resistance indices decreased with increasing CO(2) concentration in four vessels (LICA, RICA, BA, and SR). The obtained VMR parameters demonstrated exponential increases with increasing CO(2) concentration.
  
  
  CONCLUSIONS
  Using entire blood flow waveforms, this study applied separate flow dynamics during systolic and diastolic periods to obtain cerebrovascular resistance parameters and extensive flow-related information. It is the first to investigate the cerebrovascular resistance parameters under hypercapnic challenge using cine MRI. This technique could provide a useful tool for clinical application in cerebrovascular disease.
authors.affiliation: Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, Republic of China.
authors.forename: Yi-Jui
authors.initials: YJ
authors.lastname: Liu
authors.forename: Teng-Yi
authors.initials: TY
authors.lastname: Huang
authors.forename: Yi-Hsiung
authors.initials: YH
authors.lastname: Lee
authors.forename: Chun-Jung
authors.initials: CJ
authors.lastname: Juan
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000378:metabolism*; D002536:Cerebral Arteries / Q000378:metabolism* / Q000502:physiology; D002560:Cerebrovascular Circulation; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide