Proton magnetic resonance imaging with para-hydrogen induced polarization

JAN F. DECHENT; LISANDRO BULJUBASICH; LAURA M. SCHREIBER; HANS W. SPIESS; KERSTIN MÜNNEMANN

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Año: 2012 vol. 14 p. 2346 - 2352

1463-9076

A major challenge in imaging is the detection of small amounts of molecules of interest. In the case of magnetic resonance imaging (MRI) their signals are typically concealed by the large background signal of e.g. the body. This problem can be tackled by hyperpolarization which increases the NMR signals up to several orders of magnitude. However, this strategy is limited for 1H, the most widely used nucleus in NMR and MRI, because the enormous number of protons in the body screens the small amount of hyperpolarized ones. Here, we describe a method giving rise to high 1H MRI contrast for hyperpolarized molecules against a large background signal. The contrast is based on the J-coupling induced rephasing of the NMR signal of molecules hyperpolarized via PHIP and it can easily be implemented in common pulse sequences. We discuss several scenarios with different or equal dephasing times T 2 * for the hyperpolarized and thermally polarized compounds and verify our approach by experiment. This method may open up unprecedented opportunities to use the standard MRI nucleus 1H for e.g. metabolic imaging in the future.