title: Parameterization of hyperpolarized (13)C-bicarbonate-dissolution dynamic nuclear polarization.
abstract: OBJECTIVE
  (13)C metabolic MRI using hyperpolarized (13)C-bicarbonate enables preclinical detection of pH. To improve signal-to-noise ratio, experimental procedures were refined, and the influence of pH, buffer capacity, temperature, and field strength were investigated.
  
  
  METHODS
  Bicarbonate preparation was investigated. Bicarbonate was prepared and applied in spectroscopy at 1, 3, 14 T using pure dissolution, culture medium, and MCF-7 cell spheroids. Healthy rats were imaged by spectral-spatial spiral acquisition for spatial and temporal bicarbonate distribution, pH mapping, and signal decay analysis.
  
  
  RESULTS
  An optimized preparation technique for maximum solubility of 6 mol/L and polarization levels of 19-21% is presented; T1 and SNR dependency on field strength, buffer capacity, and pH was investigated. pH mapping in vivo is demonstrated.
  
  
  CONCLUSIONS
  An optimized bicarbonate preparation and experimental procedure provided improved T1 and SNR values, allowing in vitro and in vivo applications.
authors.affiliation: Institute of Medical Engineering, Technische Universität München, Munich, Germany.
authors.forename: David Johannes
authors.initials: DJ
authors.lastname: Scholz
authors.affiliation: Institute of Medical Engineering, Technische Universität München, Munich, Germany.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Otto
authors.affiliation: Institute of Medical Engineering, Technische Universität München, Munich, Germany.
authors.forename: Josef
authors.initials: J
authors.lastname: Hintermair
authors.affiliation: Institute of Medical Engineering, Technische Universität München, Munich, Germany.|Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Schilling
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Frank
authors.affiliation: Institute of Medical Engineering, Technische Universität München, Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Köllisch
authors.affiliation: Institute of Medical Engineering, General Electric Global Research, Freisinger Landstraße 50, 85748, Garching b. Munich, Germany.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Janich
authors.affiliation: Institute of Medical Engineering, General Electric Global Research, Freisinger Landstraße 50, 85748, Garching b. Munich, Germany.
authors.forename: Rolf F
authors.initials: RF
authors.lastname: Schulte
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: Institute of Medical Engineering, Technische Universität München, Munich, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Haase
authors.affiliation: Institute of Medical Engineering, General Electric Global Research, Freisinger Landstraße 50, 85748, Garching b. Munich, Germany. menzel@ge.com.
authors.forename: Marion I
authors.initials: MI
authors.lastname: Menzel
mesh_terms: D000465:Algorithms; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D002247:Carbon Isotopes; D003287:Contrast Media; D005682:Gadolinium; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D051381:Rats; D011917:Rats, Inbred Lew; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D014407:Tumor Cells, Cultured
chemical_list: D001639:Bicarbonates; D002247:Carbon Isotopes; D003287:Contrast Media; D005682:Gadolinium
keywords: Cell spheroids; Hyperpolarized 13C; MCF-7; NMR spectroscopy