title: Magnetic Resonance investigation into the mechanisms involved in the development of high-altitude cerebral edema.
abstract: Rapid ascent to high altitude commonly results in acute mountain sickness, and on occasion potentially fatal high-altitude cerebral edema. The exact pathophysiological mechanisms behind these syndromes remain to be determined. We report a study in which 12 subjects were exposed to a FiO2= 0.12 for 22 h and underwent serial magnetic resonance imaging sequences to enable measurement of middle cerebral artery velocity, flow and diameter, and brain parenchymal, cerebrospinal fluid and cerebral venous volumes. Ten subjects completed 22 h and most developed symptoms of acute mountain sickness (mean Lake Louise Score 5.4; p < 0.001 vs. baseline). Cerebral oxygen delivery was maintained by an increase in middle cerebral artery velocity and diameter (first 6 h). There appeared to be venocompression at the level of the small, deep cerebral veins (116 cm3at 2 h to 97 cm3at 22 h; p < 0.05). Brain white matter volume increased over the 22-h period (574 ml to 587 ml; p < 0.001) and correlated with cumulative Lake Louise scores at 22 h (p < 0.05). We conclude that cerebral oxygen delivery was maintained by increased arterial inflow and this preceded the development of cerebral edema. Venous outflow restriction appeared to play a contributory role in the formation of cerebral edema, a novel feature that has not been observed previously.
authors.affiliation: Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.
authors.forename: Ravjit S
authors.initials: RS
authors.lastname: Sagoo
authors.affiliation: Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.|Warwick Medical School, University of Warwick, Coventry, West Midlands, UK.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Hutchinson
authors.affiliation: College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Wright
authors.affiliation: University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors.forename: Charles
authors.initials: C
authors.lastname: Handford
authors.affiliation: Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, West Midlands, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Parsons
authors.affiliation: Department of Medical Physics, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.
authors.forename: Victoria
authors.initials: V
authors.lastname: Sherwood
authors.affiliation: Department of Medical Physics, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Wayte
authors.affiliation: Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.
authors.forename: Sanjoy
authors.initials: S
authors.lastname: Nagaraja
authors.affiliation: Department of Imaging, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.
authors.forename: Eddie
authors.initials: E
authors.lastname: Ng'Andwe
authors.affiliation: Department of Neurosurgery, Imperial College Healthcare NHS Trust, London, UK.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Wilson
authors.affiliation: Warwick Medical School, University of Warwick, Coventry, West Midlands, UK chrisimray@aim.com.|Department of Surgery, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, West Midlands, UK.|Coventry University, West Midlands, UK.
authors.forename: Christopher He
authors.initials: CH
authors.lastname: Imray
mesh_terms: D000328:Adult; D000532:Altitude Sickness / Q000473:pathology*; D001929:Brain Edema / Q000209:etiology*; D000071937:Cerebral Blood Volume; D002560:Cerebrovascular Circulation; D006801:Humans; D008279:Magnetic Resonance Imaging; D020768:Middle Cerebral Artery / Q000473:pathology / Q000503:physiopathology; D010100:Oxygen / Q000378:metabolism; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: Brain imaging; cerebral blood flow; high altitude; magnetic resonance imaging; physiology