title: Dynamic and high-resolution metabolic imaging of hyperpolarized [1-13C]-pyruvate in the rat brain using a high-performance gradient insert.
abstract: Fast chemical shift imaging (CSI) techniques are advantageous in metabolic imaging of hyperpolarized compounds due to the limited duration of the signal amplification. At the same time, reducing the acquisition time in hyperpolarized imaging does not necessarily lead to the conventional penalty in signal-to-noise ratio that occurs in imaging at thermal equilibrium polarization levels. Here a high-performance gradient insert was used in combination with undersampled spiral CSI to increase either the imaging speed or the spatial resolution of hyperpolarized (13)C metabolic imaging on a clinical 3T MR scanner. Both a single-shot sequence with a total acquisition time of 125 ms and a three-shot sequence with a nominal in-plane resolution of 1.5 mm were implemented. The k-space trajectories were measured and then used during image reconstruction. The technique was applied to metabolic imaging of the rat brain in vivo after the injection of hyperpolarized [1-(13)C]-pyruvate. Dynamic imaging afforded the measurement of region-of-interest-specific time courses of pyruvate and its metabolic products, while imaging at high spatial resolution was used to better characterize the spatial distribution of the metabolite signals.
authors.affiliation: SRI International, Neuroscience Program, Menlo Park, California 94025, USA. dirk.mayer@stanford.edu
authors.forename: Dirk
authors.initials: D
authors.lastname: Mayer
authors.forename: Yi-Fen
authors.initials: YF
authors.lastname: Yen
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Sonal
authors.initials: S
authors.lastname: Josan
authors.forename: James
authors.initials: J
authors.lastname: Tropp
authors.forename: B K
authors.initials: BK
authors.lastname: Rutt
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Hurd
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Spielman
authors.forename: Adolf
authors.initials: A
authors.lastname: Pfefferbaum
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002247:Carbon Isotopes / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D019289:Pyruvic Acid / Q000378:metabolism*; D051381:Rats
chemical_list: D002247:Carbon Isotopes; D019289:Pyruvic Acid