A general analysis of calibrated BOLD methodology for measuring CMRO2 responses: Comparison of a new approach with existing methods

► A detailed model of the BOLD signal was used to test different calibration methods. ► A new method using baseline R2′ with no inhaled gases was proposed. ► Each method was tested for its ability to control for physiological variability. ► R2′ performed reasonably well, with hypercapnia better and hyperoxia much worse. ► Accurately accounting for venous blood volume changes is important for all methods.