title: Transfer of hyperpolarization from long T1 storage nuclei to short T1 neighbors using FLOPSY-8.
abstract: Nuclei with long T1s are optimal targets for dynamic nuclear polarization (DNP). Therefore, most of the agents used in metabolic imaging and spectroscopy studies are based on carboxylic acid moieties that lack protons, a strong source of dipolar relaxation. Metabolic flux information encoded into spectra of small molecule metabolites in the form of the 13C isotopomer data cannot be accessed using standard 13C hyperpolarization methods because protonated carbons relax too quickly through T1 dipolar relaxation. It is shown here that the longitudinal mixing sequence FLOPSY-8 can be used to transfer polarization from a long T1 storage nucleus to adjacent protonated carbons so that they may be detected with high sensitivity. We demonstrate that FLOPSY-8 allows a direct readout of isotopomer populations in butyrate and glutamate in vitro.
authors.affiliation: Advanced Imaging Research Center, Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-8568, United States.
authors.forename: Karlos X
authors.initials: KX
authors.lastname: Moreno
authors.forename: Crystal
authors.initials: C
authors.lastname: Harrison
authors.forename: A Dean
authors.initials: AD
authors.lastname: Sherry
authors.forename: Craig R
authors.initials: CR
authors.lastname: Malloy
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Merritt
mesh_terms: D000465:Algorithms; D002087:Butyrates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002247:Carbon Isotopes; D002264:Carboxylic Acids / Q000737:chemistry; D004574:Electromagnetic Fields; D018698:Glutamic Acid / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008660:Metabolism
chemical_list: D002087:Butyrates; D002247:Carbon Isotopes; D002264:Carboxylic Acids; D018698:Glutamic Acid; D002244:Carbon