A Generalized Procedure for Calibrated MRI Incorporating Hyperoxia & Hypercapnia

Claudine Jolle Gauthier¹, ², Richard D. Hoge¹, ²

Calibrated MRI techniques estimate changes in cerebral metabolic rate of O2 consumption (CMRO2) from BOLD task measurements. Different calibration techniques involve estimation of M, equivalent to the maximum possible BOLD signal change, by extrapolating from smaller changes obtained during hypercapnia or hyperoxia. We present a generalization of previous BOLD signal models which can be applied to data acquired during hypercapnia, hyperoxia, or both hypercapnia and hyperoxia simultaneously (HO-HC). We demonstrate the application of this generalized model during all three manipulations. While comparable group average results were achieved, the HO-HC method yielded more robust estimates of M and CMRO2.