Increased infusion times of hyperpolarized pyruvate in D2O maintain hyperpolarized lactate generation and approach steady state metabolism

Motivation: In vivo hyperpolarized 13C MRI currently requires rapid injection of 13C-labeled probes due to the short T1-dependent lifespans of hyperpolarized substrates, limiting the acquisition window. Goal(s): Determine how to extend the short acquisition window to enhance the visualization metabolic conversions in vivo. Approach: We used D2O as dissolution solvent to elongate the T1 of [1-13C]pyruvate and explored prolonged infusion times in the murine brain. Results: Increased bolus infusion duration resulted in a significant increase in the duration of hyperpolarized [1-13C]pyruvate and [1-13C]lactate Impact: The combination of [1-13C]pyruvate in D2O, with elongated T1, and increasing injection times demonstrated an extended hyperpolarized steady level for both [1-13C]pyruvate and [1-13C]lactate in a mouse brain, leading to a more robust metabolic imaging with straightforward clinical application.