Effects of Sustained High-Altitude Hypoxia on Cerebral Hydration & Diffusion

John S. Hunt, Jr.¹, Rebecca J. Theilmann¹, Bill C. Hsu¹, Ethan Li¹, Zachary Myles Smith¹, Miriam Scadeng¹, David J. Dubowitz¹

Cerebral edema and acute mountain sickness (AMS) share many symptoms suggesting a common etiology. However, the effects of uncomplicated AMS on brain water remain controversial. To investigate the impact of high-altitude hypobaric hypoxia on cerebral water content, we measured T2 signal and ADC during normoxia, and two and seven days hypoxia. In contrast to previous hypoxic studies in a chamber at sealevel, we found a significant reduction in T2 signal and a small (non-significant) increase in ADC in the corpus callosum and caudate nuclei at altitude. This suggests barometric pressure and hydration may be important in the cerebral response to hypoxia.