Over four minutes of pyruvate T1 using chemically and physically induced deceleration of relaxation

Description

Abstract

[1-13C]pyruvate is the most widely used tracer for hyperpolarized metabolic magnetic resonance imaging, with profound applications in tumor and inflammation diagnosis as well as treatment monitoring. The most fundamental hurdle to broader application, however, remains the rapid polarization relaxation and the associated signal loss. Here, we report a method to address this challenge. Studying the nuclear spin relaxation dispersion of [1-13C]pyruvate across magnetic fields from 8 μT to 9.4 T, as a function of additives, solvents, and preparation methods, allows us to achieve T1 relaxation times of up to four minutes. Such a long T1 time could enable reliable quality control and nearly polarization loss-free transport, further boosting the power of hyperpolarized metabolic MRI. The power of the optimized protocol for T1 elongation in vitro is showcased by more than doubling of the sensitivity in a metabolic experiment.

Other

We acknowledge funding from the German Federal Ministry of Education and Research (BMBF, 03WIR6208A hyperquant), Heisenberg DFG grant (565789098), DFG (555951950, 527469039, HO-4602/2-2, HO-4602/3, EXC2167/2, FOR5042, TRR287). MOIN CC was founded with a grant from the European Regional Development Fund (ERDF) and the Zukunftsprogramm Wirtschaft of Schleswig-Holstein (Project no. 122-09-053). AJ acknowledges funding from the US National Science Foundation, award no. CHE 2505792, an award from the ACS PRF 68117-ND6, and by an unrestricted gift from Google. FT acknowledges funding from the European Union and Romania through the National Medical Project MySMIS SMIS Code 326475, and the Project ELI-RO/RDI/2024/14 SPARC funded by the Institute of Atomic Physics (Romania). JPP acknowledges funding and support by the Studienstiftung des Deutscher Volkes.