Esther AH Warnert1, Ian D Driver1, Joseph Whittaker1, and Kevin Murphy1
When modelling the BOLD
response it is often assumed that arterial blood is fully oxygenated, and that
therefore contrast is driven solely by changes in venous oxygen saturation.
Recent evidence has emerged from rodent studies indicating that precapillary
arterioles may have an oxygenation level as low as 78%. Here, we assess
arterial oxygenation in vivo in humans by using short inversion time ASL in
normoxia, as well as hyperoxia. Our results suggest that imaging the BOLD
response may not be affected by partially oxygenated arterioles.