Hyperpolarized species for NMR/MRI : parahydrogen
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Parahydrogen induced polarization (PHIP) method is based on the non-Boltzmann distribution of nuclear spin states following the hydrogenation of a substrate by parahydrogen. Absorptive and/or emissive NMR signals can be greatly enhanced, up to several orders of magnitude as compared to thermally polarized molecules.

The research in this field will complement the expertise of LSDRM in its effort to increase NMR sensitivity. The apparatus and some preliminary results are presented.

 

 

 

Parahydrogen preparation apparatus

In this apparatus, H2-gas is enriched in its parahydrogen isomer when it is cooled in the presence of a paramagnetic catalyst like ferrous oxide. It is then stored in a reservoir prior to its transfer in an NMR tube where hydrogenation occurs.

 

 

 

Hyperpolarized 1H NMR spectrum

A method named "signal amplification by reversible-exchange (SABRE)" is used that does not modify the molecular structure of the substrate, here N,N-dimethylnicotinamide at 11.7 T.

The reversible method complements another one where the substrate is irreversibly hydrogenated.

 

 

 

MRI

The same reversible method is applied for fast MRI, here with pyridine as the substrate. Hyperpolarized 1H EPI axial image of a tube immediately after the transfer of parahydrogen (left) and 40 seconds later (right), in the axial projection.

 

Maj : 10/02/2017 (2069)

 

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