Effect of Xenon-Induced Flow Activation on Xenon-Enhanced Computed Tomography Cerebral Blood Flow Calculations

Abstract
Computer simulations of stable xenon (sXe) uptake curves were used to evaluate the effect of xenon-induced flow activation on CBF calculations by xenon-enhanced computed tomography, Estimates of flow activation were based on repeated transcranial Doppler measurements of blood velocity during 4,5 minutes of sXe inhalation, The synthetic curves were generated from a generalized Kety equation that included time-varying blood flow activation, In contrast to the peak 35% increase in blood flow velocity during sXe inhalation, a standard analysis of the flow-varying synthetic curves revealed only minor 3% to 5% increases in calculated CBF. It is concluded that brief xenon inhalations can provide blood flow estimates that contain minimal bias from activation.