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Abstract #0713

Changes in Cerebral Blood Flow and Vasoreactivity to CO2 Measured by Arterial Spin Labeling After 6 Days at 4,350 M

Marjorie Villien1, Pierre Bouzat1, Thomas Rupp2, Paul Robach3, Laurent Lamalle4, Irne Troprs4, Franois Estve5, Alexandre Krainik6, Patrick Levy2, Jan M. Warnking1, Samuel Verges2

1Grenoble Institut of Neurosciences, INSERM, Grenoble, France; 2Laboratoire HP2, INSERM, Echirolles, France; 3Ecole Nationale de Ski et dAlpinisme, Chamonix, France; 4SFR1, Universit Joseph Fourier, Grenoble, France; 5ESRF, Grenoble, France; 6Clinique universitaire de neuroradiologie et d'IRM, CHU Grenoble, Grenoble, France

We assess the effects of a sojourn of 6 days at 4,350m on cerebral perfusion and on cerebrovascular reactivity to CO2 using ASL at sea level and transcranial Doppler ultrasound at altitude. We demonstrate that high altitude exposure significantly decreases vasoreactivity to CO2. The increase in CBF observed after several days at high altitude is not only the consequence of the vasodilating effect of hypoxia but probably involves other mechanisms such as changes in cerebral autoregulation and angiogenesis. This study is the first to measure cerebral perfusion and vasoreactivity with ASL after a prolonged stay at high altitude.

Keywords

acclimatization acclimatized according acute administration alternating altitude analyzed anterior arrays arterial artery assess assessed audience balance basal block blood blue breathing built cerebral channel consequence continuous corrected correlation critical custom cycles days decrease decreased decreases delay descend descent design detected eleven environ environmental exam examined excluded exhibiting exposure expressed flow fraction frames freq gray green healthy heart hypoxia immediately individual inhalation investigated involves items label labeling lake largely levy likely male massif measure measured mechanisms medical medicine methodologists middle mixture modified modulated molecular monitored motion mountain nasal normalized occurring paradigm percent perfusion physiologic physiological post posterior prior prolonged pseudo quantification questionnaire rapid reactivity realigned receive reduction regressors remain remained respiration return returned returning roach routines scanner score scores segmented separately series sickness significantly similarly since software sojourn space spin stay stayed strong structural subject subjects suffered symptom symptoms table target template tended territories territory tidal unknown vascular velocity verges