title: Metabolic imaging of hyperpolarized [1-(13) C]acetate and [1-(13) C]acetylcarnitine - investigation of the influence of dobutamine induced stress.
abstract: OBJECTIVE
  The metabolism of acetate in the heart resembles fatty acid metabolism, which is altered in several diseases like ischemia, diabetes mellitus, and heart failure. A signal-to-noise ratio (SNR) optimized imaging framework for in vivo measurements of hyperpolarized [1-(13) C]acetate and its metabolic product [1-(13) C]acetylcarnitine (ALCAR) in rats at 3 Tesla (T) is presented in this work.
  
  
  METHODS
  A spectrospatial pulse was combined with IDEAL encoding to acquire well separated metabolic maps. The influence of dobutamine induced stress onto this metabolic system was investigated in spectra and in an imaging study.
  
  
  RESULTS
  An increase of the ALCAR to acetate ratio with dobutamine induced stress was shown in slice selective spectra containing the rat hearts and skeletal muscles. Metabolic maps of acetate and ALCAR were acquired with an acceptable SNR. Quantification of the apparent conversion rate showed stable results in the heart in a time-window of 30 s. The effect of dobutamine on the signal intensities was shown to originate mainly from skeletal than cardiac muscles.
  
  
  CONCLUSIONS
  The acetate activation was mapped with hyperpolarized [1-(13) C]acetate in a clinical 3T system. Quantitative measurement of the activity was possible in the heart, indicating that dobutamine induced stress does not improve the ALCAR SNR in the heart.
authors.affiliation: Technische Universität München, Institute of Medical Engineering, Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Koellisch
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Concetta V
authors.initials: CV
authors.lastname: Gringeri
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Giaime
authors.initials: G
authors.lastname: Rancan
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Eliane V
authors.initials: EV
authors.lastname: Farell
authors.affiliation: GE Global Research, Munich, Germany.
authors.forename: Marion I
authors.initials: MI
authors.lastname: Menzel
authors.affiliation: Technische Universität München, Institute of Medical Engineering, Munich, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Haase
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.affiliation: GE Global Research, Munich, Germany.
authors.forename: Rolf F
authors.initials: RF
authors.lastname: Schulte
mesh_terms: D000085:Acetates / Q000032:analysis / Q000378:metabolism*; D000108:Acetylcarnitine / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis / Q000378:metabolism*; D057791:Cardiac Imaging Techniques; D004280:Dobutamine / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects; D008279:Magnetic Resonance Imaging; D008297:Male; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D013312:Stress, Physiological / Q000187:drug effects*
chemical_list: D000085:Acetates; D002247:Carbon Isotopes; D004280:Dobutamine; D000108:Acetylcarnitine
keywords: acetate; cardiac MRI; hyperpolarized 13C; metabolic imaging