title: Toward biocompatible nuclear hyperpolarization using signal amplification by reversible exchange: quantitative in situ spectroscopy and high-field imaging.
abstract: Signal amplification by reversible exchange (SABRE) of a substrate and parahydrogen at a catalytic center promises to overcome the inherent insensitivity of magnetic resonance. In order to apply the new approach to biomedical applications, there is a need to develop experimental equipment, in situ quantification methods, and a biocompatible solvent. We present results detailing a low-field SABRE polarizer which provides well-controlled experimental conditions, defined spins manipulations, and which allows in situ detection of thermally polarized and hyperpolarized samples. We introduce a method for absolute quantification of hyperpolarization yield in situ by means of a thermally polarized reference. A maximum signal-to-noise ratio of ∼10(3) for 148 μmol of substance, a signal enhancement of 10(6) with respect to polarization transfer field of SABRE, or an absolute (1)H-polarization level of ≈10(-2) is achieved. In an important step toward biomedical application, we demonstrate (1)H in situ NMR as well as (1)H and (13)C high-field MRI using hyperpolarized pyridine (d3) and (13)C nicotinamide in pure and 11% ethanol in aqueous solution. Further increase of hyperpolarization yield, implications of in situ detection, and in vivo application are discussed.
authors.affiliation: German Consortium for Cancer Research (DKTK) , Heidelberg, Germany.
authors.forename: Jan-Bernd
authors.initials: JB
authors.lastname: Hövener
authors.forename: Niels
authors.initials: N
authors.lastname: Schwaderlapp
authors.forename: Robert
authors.initials: R
authors.lastname: Borowiak
authors.forename: Thomas
authors.initials: T
authors.lastname: Lickert
authors.forename: Simon B
authors.initials: SB
authors.lastname: Duckett
authors.forename: Ryan E
authors.initials: RE
authors.lastname: Mewis
authors.forename: Ralph W
authors.initials: RW
authors.lastname: Adams
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Burns
authors.forename: Louise A R
authors.initials: LA
authors.lastname: Highton
authors.forename: Gary G R
authors.initials: GG
authors.lastname: Green
authors.forename: Alexandra
authors.initials: A
authors.lastname: Olaru
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hennig
authors.forename: Dominik
authors.initials: D
authors.lastname: von Elverfeldt
mesh_terms: D000431:Ethanol / Q000737:chemistry; D007536:Isomerism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008422:Materials Testing; D000432:Methanol / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D012997:Solvents; D014867:Water; D000431:Ethanol; D000432:Methanol