title: Early stage radiation-induced lung injury detected using hyperpolarized (129) Xe Morphometry: Proof-of-concept demonstration in a rat model.
abstract: Radiation-induced lung injury (RILI) is still the major dose-limiting toxicity related to lung cancer radiation therapy, and it is difficult to predict and detect patients who are at early risk of severe pneumonitis and fibrosis. The goal of this proof-of-concept preclinical demonstration was to investigate the potential of hyperpolarized (129) Xe diffusion-weighted MRI to detect the lung morphological changes associated with early stage RILI.
  
  
  
  Hyperpolarized (129) Xe MRI was performed using eight different diffusion sensitizations (0.0-115 s/cm(2) ) in a small group of control rats (n = 4) and rats 2 wk after radiation exposure (n = 5). The diffusion-weighted images were used to obtain morphological estimates of the pulmonary parenchyma including external radius (R), internal radius (r), alveolar sleeve depth (h), and mean airspace chord length (Lm ). The histological mean linear intercept (MLI) were obtained for five control and five irradiated animals.
  
  
  
  Mean R, r, and Lm were both significantly different (P < 0.02) in the irradiated rats (74 ± 17 µm, 43 ± 12 µm, and 54 ± 17 µm, respectively) compared with the control rats (100 ± 12 µm, 67 ± 10 µm, and 79 ± 12 µm, respectively). Changes in measured Lm values were consistent with changes in MLI values observed by histology.
  
  
  
  Hyperpolarized (129) Xe MRI provides a way to detect and measure regional microanatomical changes in lung parenchyma in a preclinical model of RILI. Magn Reson Med 75:2421-2431, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.
authors.forename: Alexei
authors.initials: A
authors.lastname: Ouriadov
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.|Department of Medical Biophysics, Western University, London, Ontario, Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: Fox
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.
authors.forename: Elaine
authors.initials: E
authors.lastname: Hegarty
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.|Department of Medical Biophysics, Western University, London, Ontario, Canada.
authors.forename: Grace
authors.initials: G
authors.lastname: Parraga
authors.affiliation: Department of Medical Biophysics, Western University, London, Ontario, Canada.|Department of Physics and Astronomy, Western University, London, Ontario, Canada.
authors.forename: Eugene
authors.initials: E
authors.lastname: Wong
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada.|Department of Medical Biophysics, Western University, London, Ontario, Canada.|Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Giles E
authors.initials: GE
authors.lastname: Santyr
mesh_terms: D000818:Animals; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006651:Histocytochemistry; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D055370:Lung Injury / Q000000981:diagnostic imaging* / Q000473:pathology; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014979:Xenon Isotopes
chemical_list: D014979:Xenon Isotopes
keywords: ADC; RILI; anisotropy; hyperpolarized; lung; morphometry; xenon-129