Transportable hyperpolarized metabolites

Xiao Ji,Sami Jannin,David Gajan,Lyndon Emsley,Aaron J Rossini,Geoffrey Bodenhausen,Jonas Milani,Basile Vuichoud,Aurélien Bornet

doi:10.1038/ncomms13975

Abstract

Nuclear spin hyperpolarization of 13C-labelled metabolites by dissolution dynamic nuclear polarization can enhance the NMR signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by MRI. However, because of the short lifetime of the hyperpolarized magnetization (typically <1 min), the polarization process must be carried out close to the point of use. Here we introduce a concept that markedly extends hyperpolarization lifetimes and enables the transportation of hyperpolarized metabolites. The hyperpolarized sample can thus be removed from the polarizer and stored or transported for use at remote MRI or NMR sites. We show that hyperpolarization in alanine and glycine survives 16 h storage and transport, maintaining overall polarization enhancements of up to three orders of magnitude.

Highlights

Nuclear spin hyperpolarization of 13C-labelled metabolites by dissolution dynamic nuclear polarization can enhance the nuclear magnetic resonance (NMR) signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by magnetic resonance imaging (MRI)
After DNP at low temperature, the glassy mixture is rapidly melted at high field inside the DNP polarizer, and the resulting hyperpolarized solution is rapidly transferred to an NMR or magnetic resonance imaging (MRI) magnet
After the 13C polarization has achieved a satisfactory level, the microwave irradiation is switched off and the sample temperature is increased from 1.2 to 4.2 K, and the protons in both radical-rich phase (RRP) and radical-free phase (RFP) phases relax towards thermal equilibrium within minutes

Summary

Introduction

Nuclear spin hyperpolarization of 13C-labelled metabolites by dissolution dynamic nuclear polarization can enhance the NMR signals of metabolites by several orders of magnitude, which has enabled in vivo metabolic imaging by MRI. The concept of DNP relayed by spin diffusion has been generalized to micro-particulate samples by Emsley and co-workers, who showed that this could lead to substantial polarization in ordinary organic solids and provide information about domain structures, for example, in pharmaceutical formulations[22,23,24]. All of these studies were performed in combination with magic angle spinning DNP at temperatures B100 K. In this communication, capitalizing on this concept of DNP relayed by spin diffusion, we show how micro-particles can be hyperpolarized in trapped states with high polarization a μm SEM of (1-13C) sodium pyruvate

Methods

Results

Conclusion