title: A multisample dissolution dynamic nuclear polarization system for serial injections in small animals.
abstract: Several in vivo applications of dissolution dynamic nuclear polarization (DNP) require rapid successive injections of hyperpolarized substrates. Here we present the design and performance of a custom-built multisample dissolution DNP setup for small animal research.
  
  
  
  The DNP setup consists of a commercial wide-bore magnet charged to 3.35 T, a cryostat, a 94-GHz microwave source, and a custom-built skeleton that accommodates four identical sample sticks. Each sample stick features a dissolver locked into the skeleton port and a lifter, which permits moving the sample cup out of the liquid helium bath for dissolution.
  
  
  
  The dissolution of the first sample was triggered after 2 hours of polarization buildup during single-shot operation of the cryostat. Thereafter, a time window of 75-90 min was available to dissolve the remaining three polarized samples. The average liquid state polarization over all four sticks was measured as 18.7% ± 2.3% for [1-13C] pyruvate 30 s after dissolution. In vivo applicability of the setup using serial injections of [1-13C] pyruvate to study cardiac metabolism in rats revealed good reproducibility.
  
  
  
  The proposed four-sample DNP insert provides reproducible liquid state polarization of [1-13C] pyruvate and allows for rapid repeat injections in small animals. Magn Reson Med 77:904-910, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.|Laboratory of Physical Chemistry, ETH Zurich, Switzerland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Krajewski
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Wespi
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Busch
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Wissmann
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Kwiatkowski
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
authors.forename: Jonas
authors.initials: J
authors.lastname: Steinhauser
authors.affiliation: Laboratory of Physical Chemistry, ETH Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Batel
authors.affiliation: Laboratory of Physical Chemistry, ETH Zurich, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Ernst
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D004867:Equipment Design; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D007267:Injections / Q000295:instrumentation; D019344:Lactic Acid / Q000008:administration & dosage / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D019289:Pyruvic Acid / Q000008:administration & dosage / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001639:Bicarbonates; D019344:Lactic Acid; D019289:Pyruvic Acid
keywords: dissolution DNP; dynamic nuclear polarization; metabolic imaging; multi-sample DNP; small animal