Feasibility of mapping the tissue mass corrected bioscale of cerebral metabolic rate of oxygen consumption using 17-oxygen and 23-sodium MR imaging in a human brain at 9.4Â T

The reduction of molecular oxygen to water is the final step of oxidative phosphorylation that couples adenosine triphosphate production to the reoxidation of reducing equivalents formed during the oxidation of glucose to carbon dioxide. This coupling makes the cerebral metabolic rate of oxygen consumption (CMRO2) an excellent reflection of the metabolic health of the brain. A multi-nuclear magnetic resonance (MR) imaging based method for CMRO2 mapping is proposed. Oxygen consumption is determined by applying a new three-phase metabolic model for water generation and clearance to the changing 17-oxygen (17O) labeled water MR signal measured using quantitative 17O MR imaging during inhalation of 17O-enriched oxygen gas. These CMRO2 data are corrected for the regional brain tissue mass computed from quantitative 23-sodium MR imaging of endogenous tissue sodium ions to derive quantitative results of oxygen consumption in micromoles O2/g tissue/minute that agree with literature results reported from positron emission tomography. The proposed technique is demonstrated in the human brain using a 9.4 T MR scanner optimized for human brain imaging.