title: Evaluation of oxygen sensitivity of hyperpolarized helium imaging for the detection of pulmonary ischemia.
abstract: OBJECTIVE
  In this study, a new model of pulmonary embolism in rats was developed and tested, to examine if hyperpolarized (HP) (3) He MR images can measure impairment of the exchange of oxygen from the airspaces to the blood during pulmonary embolism.
  
  
  METHODS
  HP (3) He MRI was used to image six treatment-group rats in which a branch of the pulmonary artery was embolized, and six control-group rats. HP (3) He MR images were used to calculate the initial partial pressure of oxygen (pO ) and the rate of oxygen depletion (R) in rat lungs.
  
  
  RESULTS
  The pO was significantly higher in the ischemic lung than in the contralateral normal side, and pO was significantly higher in the ischemic lung than in both sides of the control lungs. Mean R in ischemic lungs was significantly lower than in the contralateral lungs, and mean R in ischemic lungs was also significantly lower than in both control lungs.
  
  
  CONCLUSIONS
  These results demonstrate that pO and R, as measured by the T1 decay of HP (3) He, are sensitive to pulmonary ischemia in rats, confirming the findings in studies performed in large animal models of pulmonary ischemia.
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Ronn P
authors.initials: RP
authors.lastname: Walvick
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.|Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada.
authors.forename: John P
authors.initials: JP
authors.lastname: Roche
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Austin L
authors.initials: AL
authors.lastname: Reno
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gounis
authors.affiliation: Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada.|Lakehead University, Thunder Bay, Ontario, Canada.
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Albert
mesh_terms: D000818:Animals; D006371:Helium / Q000737:chemistry*; D007091:Image Processing, Computer-Assisted; D007511:Ischemia / Q000000981:diagnostic imaging* / Q000473:pathology; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology*; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D010100:Oxygen / Q000737:chemistry*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D006371:Helium; D010100:Oxygen
keywords: Digital Subtraction Angiography; Hyperpolarized Helium; Pulmonary Embolism; Small Animal Imaging