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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.