First hyperpolarized [2-C]pyruvate MR studies of human brain metabolism.

We developed methods for the preparation of hyperpolarized (HP) sterile [2-C]pyruvate to test its feasibility in first-ever human NMR studies following FDA-IND & IRB approval. Spectral results using this MR stable-isotope imaging approach demonstrated the feasibility of investigating human cerebral energy metabolism by measuring the dynamic conversion of HP [2-C]pyruvate to [2-C]lactate and [5-C]glutamate in the brain of four healthy volunteers. Metabolite kinetics, signal-to-noise (SNR) and area-under-curve (AUC) ratios, and calculated [2-C]pyruvate to [2-C]lactate conversion rates (k) were measured and showed similar but not identical inter-subject values. The k measurements were equivalent with prior human HP [1-C]pyruvate measurements.