Optimization of a [1-13C]pyruvic acid sample preparation for clinical hyperpolarization

Motivation: Because of the nonrenewable out of equilibrium magnetization, hyperpolarized (HP) MRI is critically SNR-limited. In that context, more initial polarization should translate into superior diagnostic performances. Goal(s): Optimizing the [1-13C]pyruvic acid preparation for a 5T clinical hyperpolarizer system. Approach: Optimizing the sample preparation by measuring the electronic T1 (T1e) at actual clinical DNP conditions using in situ LOD-ESR measurements. Results: Adding 0.5mM of DOTA-Gd chelate to the standard [1-13C]pyruvic acid clinical preparation led to an optimal T1e and consequent 1.5-fold increase in liquid state polarization. Impact: Hyperpolarized-MRI diagnostic capability depends on the initial polarization of the contrast agent. Clinical polarizers are complex and expensive machines. We propose an easy to implement optimized sample preparation leading to a 50% SNR increase without any hardware modification.