title: Functional magnetic resonance imaging of regional cerebral blood oxygenation changes during breath holding.
abstract: OBJECTIVE
  Recently, noninvasive MRI methods have been developed that are now capable of detecting and mapping regional hemodynamic responses to various stress tests, which involve the use of vasoactive substances such as acetazolamide or inhalation of carbon dioxide. The aim of this study was to assess regional cerebral blood oxygenation changes during breath holding at 1.5 T.
  
  
  METHODS
  In 6 healthy volunteers, T2*-weighted gradient echo images were acquired for a total dynamic scanning time of 10 minutes during alternating periods of breath holding and normal breathing at 40-second intervals after inspiration, at 30-second intervals after expiration, and at 18 seconds after expiration. To quantify the relative signal changes, 2.5-minute baseline image sampling with normal breathing was carried out.
  
  
  RESULTS
  Repeated challenges of breath holding of various durations induced an overall rise in blood oxygen level-dependent (BOLD) signal intensities. In general, BOLD signal intensity increases were greatest in gray matter and nonsignificant in white matter. Depending on the breath-holding duration and techniques, BOLD signal intensity increases of all activated pixels varied from 0.8% to 3.5%.
  
  
  CONCLUSIONS
  The present study demonstrates that cerebral blood oxygenation changes during breath holding can be detected by means of fMRI at 1.5 T. The breath-holding test, a short and noninvasive method to study cerebral hemodynamics with fMRI, could become a useful alternative to the acetazolamide or CO2 test.
authors.affiliation: Department of Radiology, University of Stanford, Stanford, Calif. USA. andreas@s-word.stanford.edu
authors.forename: A
authors.initials: A
authors.lastname: Kastrup
authors.forename: T Q
authors.initials: TQ
authors.lastname: Li
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: G H
authors.initials: GH
authors.lastname: Glover
authors.forename: M E
authors.initials: ME
authors.lastname: Moseley
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007040:Hypoventilation / Q000097:blood* / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood*; D013997:Time Factors
chemical_list: D010100:Oxygen