title: Effects of ozone exposure in rat lungs investigated with hyperpolarized 3 He MRI.
abstract: OBJECTIVE
  To investigate the effects of subchronic ozone exposure on rat lung ventilation using hyperpolarized (HP) (3)He MRI.
  
  
  METHODS
  A total of 24 Sprague-Dawley rats, distributed in one control group and four groups exposed to 0.5 ppm ozone concentration for two days or six days, either continuously (22 hours/day) or alternatingly (12 hours/day). A three-step MRI protocol was designed and applied to each animal, including: 1) (3)He gas distribution images acquired at inspiratory capacity, 2) measurements of intrapulmonary (3)He diffusion coefficients, and 3) dynamic ventilation acquisitions performed during lung filling with (3)He.
  
  
  RESULTS
  No differentiation between animals exposed to ozone and control animals was observed from the ventilation images obtained at inspiratory capacity. The (3)He diffusion coefficients were not statistically different from one group to another. Ventilation defects, appearing as delayed lung filling regions and heterogeneous lung filling, were observed in the dynamic lung ventilation image series. The percentage of animals with ventilation defects in the control, two-day, and six-day exposed groups were equal to 20%, 43% and 75%, respectively. In the subgroup of the animals exposed six days for 12 hours per day, the percentage of animals exhibiting ventilation defects was equal to 85%.
  
  
  CONCLUSIONS
  Heterogeneous obstructive patterns in an experimental animal model of subchronic ozone exposure were observed using HP (3)He MRI.
authors.affiliation: Université Lyon 1, Laboratoire de Resonance Magnétique Nucleaire (CREATIS-LRMN), Lyon, France. yannick.cremillieux@univ-lyon1.fr
authors.forename: Yannick
authors.initials: Y
authors.lastname: Crémillieux
authors.forename: Stéphane
authors.initials: S
authors.lastname: Servais
authors.forename: Yves
authors.initials: Y
authors.lastname: Berthezène
authors.forename: David
authors.initials: D
authors.lastname: Dupuich
authors.forename: Aurélien
authors.initials: A
authors.lastname: Boussouar
authors.forename: Vasile
authors.initials: V
authors.lastname: Stupar
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Pequignot
mesh_terms: D000818:Animals; D006371:Helium; D007554:Isotopes; D008168:Lung / Q000187:drug effects* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010083:Oxidants, Photochemical / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007554:Isotopes; D010083:Oxidants, Photochemical; D006371:Helium; D010126:Ozone