title: In situ and ex situ low-field NMR spectroscopy and MRI endowed by SABRE hyperpolarization.
abstract: By using 5.75 and 47.5 mT nuclear magnetic resonance (NMR) spectroscopy, up to 10(5)-fold sensitivity enhancement through signal amplification by reversible exchange (SABRE) was enabled, and subsecond temporal resolution was used to monitor an exchange reaction that resulted in the buildup and decay of hyperpolarized species after parahydrogen bubbling. We demonstrated the high-resolution low-field proton magnetic resonance imaging (MRI) of pyridine in a 47.5 mT magnetic field endowed by SABRE. Molecular imaging (i.e. imaging of dilute hyperpolarized substances rather than the bulk medium) was conducted in two regimes: in situ real-time MRI of the reaction mixture (in which pyridine was hyperpolarized), and ex situ MRI (in which hyperpolarization decays) of the liquid hyperpolarized product. Low-field (milli-Tesla range, e.g. 5.75 and 47.5 mT used in this study) parahydrogen-enhanced NMR and MRI, which are free from the limitations of high-field magnetic resonance (including susceptibility-induced gradients of the static magnetic field at phase interfaces), potentially enables new imaging applications as well as differentiation of hyperpolarized chemical species on demand by exploiting spin manipulations with static and alternating magnetic fields.
authors.affiliation: Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, 3 A Institutskaya St. Novosibirsk 630090 (Russia); Novosibirsk State University, 2 Pirogova St. Novosibirsk 630090 (Russia).
authors.forename: Danila A
authors.initials: DA
authors.lastname: Barskiy
authors.forename: Kirill V
authors.initials: KV
authors.lastname: Kovtunov
authors.forename: Igor V
authors.initials: IV
authors.lastname: Koptyug
authors.forename: Ping
authors.initials: P
authors.lastname: He
authors.forename: Kirsten A
authors.initials: KA
authors.lastname: Groome
authors.forename: Quinn A
authors.initials: QA
authors.lastname: Best
authors.forename: Fan
authors.initials: F
authors.lastname: Shi
authors.forename: Boyd M
authors.initials: BM
authors.lastname: Goodson
authors.forename: Roman V
authors.initials: RV
authors.lastname: Shchepin
authors.forename: Milton L
authors.initials: ML
authors.lastname: Truong
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Coffey
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Waddell
authors.forename: Eduard Y
authors.initials: EY
authors.lastname: Chekmenev
mesh_terms: D007495:Iridium / Q000032:analysis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D057054:Molecular Imaging / Q000379:methods; D011725:Pyridines / Q000032:analysis
chemical_list: D011725:Pyridines; D007495:Iridium; C023666:pyridine
keywords: NMR spectroscopy; SABRE; hyperpolarization; iridium; molecular imaging