A New Approach for Venous Blood Oxygenation & Calibrated BOLD using Hyperoxia

Ian Driver¹, Emma Hall¹, Susan Pritchard¹, Susan Francis¹, Penny Gowland¹

Current methods for BOLD calibration assume Grubbs coupling constant between cerebral blood flow and blood volume, which is poorly characterised, measured for total blood volume and likely to vary between brain regions and subjects. Here we present a new method based on hyperoxia for the measurement of venous blood volume (vCBV), blood oxygenation and oxygen metabolism (CMRO2) changes on neuronal activation without the need to assume any flow/volume coupling relationship. Data is presented for a motor task where changes were of 322% for vCBV, 383% for blood oxygenation, and 306% for CMRO2 which is in close agreement to literature.