title: Regional mapping of gas uptake by blood and tissue in the human lung using hyperpolarized xenon-129 MRI.
abstract: OBJECTIVE
  To develop a breathhold acquisition for regional mapping of ventilation and the fractions of hyperpolarized xenon-129 (Xe129) dissolved in tissue (lung parenchyma and plasma) and red blood cells (RBCs), and to perform an exploratory study to characterize data obtained in human subjects.
  
  
  METHODS
  A three-dimensional, multi-echo, radial-trajectory pulse sequence was developed to obtain ventilation (gaseous Xe129), tissue, and RBC images in healthy subjects, smokers, and asthmatics. Signal ratios (total dissolved Xe129 to gas, tissue-to-gas, RBC-to-gas, and RBC-to-tissue) were calculated from the images for quantitative comparison.
  
  
  RESULTS
  Healthy subjects demonstrated generally uniform values within coronal slices, and a gradient in values along the anterior-to-posterior direction. In contrast, images and associated ratio maps in smokers and asthmatics were generally heterogeneous and exhibited values mostly lower than those in healthy subjects. Whole-lung values of total dissolved Xe129 to gas, tissue-to-gas, and RBC-to-gas ratios in healthy subjects were significantly larger than those in diseased subjects.
  
  
  CONCLUSIONS
  Regional maps of tissue and RBC fractions of dissolved Xe129 were obtained from a short breathhold acquisition, well tolerated by healthy volunteers and subjects with obstructive lung disease. Marked differences were observed in spatial distributions and overall amounts of Xe129 dissolved in tissue and RBCs among healthy subjects, smokers and asthmatics.
authors.affiliation: Department of Biomedical Engineering, University of Virginia School of Medicine, Charlottesville, Virginia, USA.
authors.forename: Kun
authors.initials: K
authors.lastname: Qing
authors.forename: Kai
authors.initials: K
authors.lastname: Ruppert
authors.forename: Yun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jaime F
authors.initials: JF
authors.lastname: Mata
authors.forename: G Wilson
authors.initials: GW
authors.lastname: Miller
authors.forename: Y Michael
authors.initials: YM
authors.lastname: Shim
authors.forename: Chengbo
authors.initials: C
authors.lastname: Wang
authors.forename: Iulian C
authors.initials: IC
authors.lastname: Ruset
authors.forename: F William
authors.initials: FW
authors.lastname: Hersman
authors.forename: Talissa A
authors.initials: TA
authors.lastname: Altes
authors.forename: John P
authors.initials: JP
authors.lastname: Mugler
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008168:Lung / Q000378:metabolism*; D008171:Lung Diseases / Q000175:diagnosis / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011659:Pulmonary Gas Exchange; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014979:Xenon Isotopes / Q000008:administration & dosage / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D014979:Xenon Isotopes
keywords: gas uptake; hyperpolarized xenon-129; lung imaging; pulmonary disease