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.