title: Storage of hydrogen spin polarization in long-lived 13C2 singlet order and implications for hyperpolarized magnetic resonance imaging.
abstract: Hyperpolarized magnetic resonance imaging (MRI) is a powerful technique enabling real-time monitoring of metabolites at concentration levels not accessible by standard MRI techniques. A considerable challenge this technique faces is the T1 decay of the hyperpolarization upon injection into the system under study. Here we show that A(n)A'(n)XX' spin systems such as (13)C2-1,2-diphenylacetylene ((13)C2-DPA) sustain long-lived polarization for both (13)C and (1)H spins with decay constants of almost 4.5 min at high magnetic fields of up to 16.44 T without spin-locking; the T1 of proton polarization is only 3.8 s. Therefore, storage of the proton polarization in a (13)C2-singlet state causes a 69-fold extension of the spin lifetime. Notably, this extension is demonstrated with proton-only pulse sequences, which can be readily implemented on standard clinical scanners.
authors.affiliation: Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Yesu
authors.initials: Y
authors.lastname: Feng
authors.forename: Thomas
authors.initials: T
authors.lastname: Theis
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Liang
authors.forename: Qiu
authors.initials: Q
authors.lastname: Wang
authors.forename: Pei
authors.initials: P
authors.lastname: Zhou
authors.forename: Warren S
authors.initials: WS
authors.lastname: Warren
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives* / Q000737:chemistry; D002247:Carbon Isotopes; D006859:Hydrogen / Q000737:chemistry*; D008279:Magnetic Resonance Imaging
chemical_list: D002247:Carbon Isotopes; C044735:biphenylacetylene; D006859:Hydrogen; D000114:Acetylene