Nicholas P. Blockley1, Valerie E M Griffeth2, Peter Jezzard1, Daniel P. Bulte1
1FMRIB, University of Oxford, Oxford, United Kingdom; 2Center for Functional MRI, University of California San Diego, La Jolla, CA, United States
The calibrated BOLD technique is conventionally used to quantify the BOLD response in terms of changes in oxygen metabolism. Recently such methods were extended to produce absolute measurements of the resting oxygen extraction fraction. However, the sensitivity of this new method to intersubject physiological variability, or to a breakdown of the physiological assumptions that underpin the method, has not been explored. In this work we show that this method is relatively insensitive to physiological variability, but reveal a potential systematic error in the current analysis approach.