title: MR tagging of human lungs using hyperpolarized 3He gas.
abstract: OBJECTIVE
  To evaluate the use of spin-tagging in conjunction with hyperpolarized gas imaging for monitoring lung ventilation and gas diffusion.
  
  
  METHODS
  Images were taken at 0.15 T using single shot RARE, with hyperpolarized (3)He gas prepared by the metastability exchange technique. Sinusoidal modulation of the longitudinal magnetization (tag) was produced by two 90-degree rf pulses separated by a gradient pulse. The diffusion of (3)He gas in the lungs was measured by monitoring the decay of the tags. This study was conducted on a 25-year-old, male, healthy volunteer.
  
  
  RESULTS
  Clear tags in hyperpolarized (3)He gas both in vivo and in vitro were generated. The relative movement of the lung compared to a static, partial breath-hold was measured following inspiration or expiration. The diffusion coefficient of (3)He in the lungs was found to be 0.02 +/- 0.005 cm(2)seconds(-1).
  
  
  CONCLUSIONS
  The spin-tagging of hyperpolarized (3)He in the lungs is possible, and allows regional lung movements to be measured following inspiration and expiration. It also allows quantification of the diffusion of the (3)He gas.
authors.affiliation: School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK. john.owers-bradley@nottingham.ac.uk
authors.forename: John R
authors.initials: JR
authors.lastname: Owers-Bradley
authors.forename: Stanislao
authors.initials: S
authors.lastname: Fichele
authors.forename: Abdelmalek
authors.initials: A
authors.lastname: Bennattayalah
authors.forename: Colin J Smith
authors.initials: CJ
authors.lastname: McGloin
authors.forename: Richard W
authors.initials: RW
authors.lastname: Bowtell
authors.forename: Paul S
authors.initials: PS
authors.lastname: Morgan
authors.forename: Alan R
authors.initials: AR
authors.lastname: Moody
mesh_terms: D000328:Adult; D006371:Helium; D006801:Humans; D007554:Isotopes; D008168:Lung / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology; D012016:Reference Values
chemical_list: D007554:Isotopes; D006371:Helium