title: Detecting pulmonary capillary blood pulsations using hyperpolarized xenon-129 chemical shift saturation recovery (CSSR) MR spectroscopy.
abstract: OBJECTIVE
  To investigate whether chemical shift saturation recovery (CSSR) MR spectroscopy with hyperpolarized xenon-129 is sensitive to the pulsatile nature of pulmonary blood flow during the cardiac cycle.
  
  
  METHODS
  A CSSR pulse sequence typically uses radiofrequency (RF) pulses to saturate the magnetization of xenon-129 dissolved in lung tissue followed, after a variable delay time, by an RF excitation and subsequent acquisition of a free-induction decay. Thereby it is possible to monitor the uptake of xenon-129 by lung tissue and extract physiological parameters of pulmonary gas exchange. In the current studies, the delay time was instead held at a constant value, which permitted observation of xenon-129 gas uptake as a function of breath-hold time. CSSR studies were performed in 13 subjects (10 healthy, 2 chronic obstructive pulmonary disease [COPD], 1 second-hand smoke exposure), holding their breath at total lung capacity.
  
  
  RESULTS
  The areas of the tissue/plasma and the red-blood-cell peaks in healthy subjects varied by an average of 1.7±0.7% and 15.1±3.8%, respectively, during the cardiac cycle. In 2 subjects with COPD these peak pulsations were not detectable during at least part of the measurement period.
  
  
  CONCLUSIONS
  CSSR spectroscopy is sufficiently sensitive to detect oscillations in the xenon-129 gas-uptake rate associated with the cardiac cycle.
authors.affiliation: Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.|Department of Pulmonary Medicine, Cincinnati Children's Hospital, Cincinnati, Ohio, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Ruppert
authors.affiliation: Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Talissa A
authors.initials: TA
authors.lastname: Altes
authors.affiliation: Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: Jaime F
authors.initials: JF
authors.lastname: Mata
authors.affiliation: Xemed, LLC, Durham, New Hampshire, USA.|Department of Physics, University of New Hampshire, Durham, New Hampshire, USA.
authors.forename: Iulian C
authors.initials: IC
authors.lastname: Ruset
authors.affiliation: Xemed, LLC, Durham, New Hampshire, USA.|Department of Physics, University of New Hampshire, Durham, New Hampshire, USA.
authors.forename: F William
authors.initials: FW
authors.lastname: Hersman
authors.affiliation: Center for In-vivo Hyperpolarized Gas MR Imaging, Department of Radiology & Medical Imaging, University of Virginia, Charlottesville, Virginia, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Mugler
mesh_terms: D000328:Adult; D002196:Capillaries / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply* / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D014979:Xenon Isotopes / Q000032:analysis / Q000737:chemistry*; D055815:Young Adult
chemical_list: D014979:Xenon Isotopes
keywords: CSSR spectroscopy; chemical shift saturation recovery; hyperpolarized xenon-129