title: Phase-contrast MRI measurement of systolic cerebrospinal fluid peak velocity (CSFV(peak)) in the aqueduct of Sylvius: a noninvasive tool for measurement of cerebral capacity.
abstract: BACKGROUND
  Cerebrospinal fluid (CSF) outflow to intra- and extracranial subarachnoid spaces caused by arterial inflow to the brain predominantly compensates systolic increases in cerebral blood volume. Phase-contrast magnetic resonance imaging is a new tool for noninvasive assessment of CSF displacement by measuring CSF peak velocity (CSFV(Peak)). The authors tested this new tool in an experimental human model of increased intracranial pressure and reduced cerebral capacity by means of continuous positive airway pressure (CPAP) breathing.
  
  
  METHODS
  The authors investigated systolic CSFV(Peak) in the aqueduct of Sylvius in 11 awake, normocapnic (end-tidal carbon dioxide [ET(CO2)] = 40 mmHg) volunteers without CPAP and at two different CPAP levels (6 and 12 cm H2O) by means of electroencephalography-gated phase-contrast magnetic resonance imaging.
  
  
  RESULTS
  Administration of 6 cm H2O CPAP did not change systolic CSFV(Peak) (-4.9+/-2.8 cm/s vs. control: -5.1+/-2.7 cm/s), whereas 12 cm H2O CPAP significantly reduced systolic CSFV(Peak) (-4.0+/-1.8 cm/s vs. control: -5.1+/-2.7 cm/s; P < 0.05).
  
  
  CONCLUSIONS
  These findings in awake volunteers show that monitoring CSFV(Peak) in the aqueduct of Sylvius is a sensitive method for detecting even minor impairment of cerebral capacity caused by experimentally induced increases in intracranial pressure.
authors.affiliation: Department of Anesthesia and Intensive Care Medicine, The Leopold-Franzens University of Innsbruck, Austria. christian.kolbitsch@uibk.ac.at
authors.forename: C
authors.initials: C
authors.lastname: Kolbitsch
authors.forename: M
authors.initials: M
authors.lastname: Schocke
authors.forename: I H
authors.initials: IH
authors.lastname: Lorenz
authors.forename: C
authors.initials: C
authors.lastname: Kremser
authors.forename: F
authors.initials: F
authors.lastname: Zschiegner
authors.forename: K P
authors.initials: KP
authors.lastname: Pfeiffer
authors.forename: S
authors.initials: S
authors.lastname: Felber
authors.forename: F
authors.initials: F
authors.lastname: Aichner
authors.forename: C
authors.initials: C
authors.lastname: Hörmann
authors.forename: A
authors.initials: A
authors.lastname: Benzer
mesh_terms: D000328:Adult; D001810:Blood Volume; D002555:Cerebrospinal Fluid / Q000502:physiology*; D006801:Humans; D007427:Intracranial Pressure; D008279:Magnetic Resonance Imaging; D008297:Male; D011175:Positive-Pressure Respiration; D013599:Systole