title: Hyperpolarization without persistent radicals for in vivo real-time metabolic imaging.
abstract: Hyperpolarized substrates prepared via dissolution dynamic nuclear polarization have been proposed as magnetic resonance imaging (MRI) agents for cancer or cardiac failure diagnosis and therapy monitoring through the detection of metabolic impairments in vivo. The use of potentially toxic persistent radicals to hyperpolarize substrates was hitherto required. We demonstrate that by shining UV light for an hour on a frozen pure endogenous substance, namely the glucose metabolic product pyruvic acid, it is possible to generate a concentration of photo-induced radicals that is large enough to highly enhance the (13)C polarization of the substance via dynamic nuclear polarization. These radicals recombine upon dissolution and a solution composed of purely endogenous products is obtained for performing in vivo metabolic hyperpolarized (13)C MRI with high spatial resolution. Our method opens the way to safe and straightforward preclinical and clinical applications of hyperpolarized MRI because the filtering procedure mandatory for clinical applications and the associated pharmacological tests necessary to prevent contamination are eliminated, concurrently allowing a decrease in the delay between preparation and injection of the imaging agents for improved in vivo sensitivity.
authors.affiliation: Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Tim R
authors.initials: TR
authors.lastname: Eichhorn
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Takado
authors.forename: Najat
authors.initials: N
authors.lastname: Salameh
authors.forename: Andrea
authors.initials: A
authors.lastname: Capozzi
authors.forename: Tian
authors.initials: T
authors.lastname: Cheng
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Hyacinthe
authors.forename: Mor
authors.initials: M
authors.lastname: Mishkovsky
authors.forename: Christophe
authors.initials: C
authors.lastname: Roussel
authors.forename: Arnaud
authors.initials: A
authors.lastname: Comment
mesh_terms: D000818:Animals; D002247:Carbon Isotopes / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005583:Fourier Analysis; D005609:Free Radicals / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008660:Metabolism / Q000502:physiology*; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D019289:Pyruvic Acid; D014466:Ultraviolet Rays
chemical_list: D002247:Carbon Isotopes; D005609:Free Radicals; D019289:Pyruvic Acid
keywords: acetate; lactate; metabolism; nuclear magnetic resonance; pyruvate