title: Echo-planar MR imaging of dissolved hyperpolarized 129Xe.
abstract: OBJECTIVE
  The feasibility of hyperpolarized 129Xe for fast MR angiography (MRA) was evaluated using the echo-planar imaging (EPI) technique.
  
  
  METHODS
  Hyperpolarized Xe gas was dissolved in ethanol, a carrier agent with high solubility for Xe (Ostwald solubility coefficient 2.5) and long relaxation times. The dissolved Xe was injected as a bolus into a flow phantom where the mean flow velocity was 15 cm/s. Ultrafast EPI images with 44 ms scan time were acquired of the flowing bolus and the signal-to-noise ratios (SNR) were measured.
  
  
  RESULTS
  The relaxation times of hyperpolarized Xe in ethanol were measured to T1=160+/-11 s and T2 approximately 20 s. The resulting images of the flowing liquid were of reasonable quality and had an SNR of about 70.
  
  
  CONCLUSIONS
  Based on the SNR of the obtained Xe EPI images, it was estimated that rapid in vivo MRA with 129Xe may be feasible, provided that an efficient, biologically acceptable carrier for Xe can be found and polarization levels of more than 25% can be achieved in isotopically enriched 129Xe.
authors.affiliation: Department of Experimental Research, Malmö University Hospital, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Månsson
authors.forename: E
authors.initials: E
authors.lastname: Johansson
authors.forename: J
authors.initials: J
authors.lastname: Svensson
authors.forename: L E
authors.initials: LE
authors.lastname: Olsson
authors.forename: F
authors.initials: F
authors.lastname: Ståhlberg
authors.forename: J S
authors.initials: JS
authors.lastname: Petersson
authors.forename: K
authors.initials: K
authors.lastname: Golman
mesh_terms: D017352:Echo-Planar Imaging; D005240:Feasibility Studies; D018810:Magnetic Resonance Angiography / Q000379:methods*; D014979:Xenon Isotopes
chemical_list: D014979:Xenon Isotopes