title: Assessment of repeatability of hyperpolarized gas MR ventilation functional imaging in cystic fibrosis.
abstract: OBJECTIVE
  Hyperpolarized (HP) gas magnetic resonance imaging (MRI) is an advanced imaging technique that provides high-resolution regional information on lung function without using ionizing radiation. Before this modality can be considered for assessing clinical or investigational interventions, baseline repeatability needs to be established. We assessed repeatability of lung function measurement using HP helium-3 MRI (HP (3)He MRI) in a small cohort of patients with cystic fibrosis (CF).
  
  
  METHODS
  We examined repeatability of HP (3)He MR images of five patients with CF in four scanning sessions over a 4-week period. We acquired images on a Philips 3.0 Tesla Achieva MRI scanner using a quadrature, flexible, wrap-around, (3)He radiofrequency coil with a fast gradient-echo pulse sequence. We determined ventilation volume and ventilation defect volume using an advanced semiautomatic segmentation algorithm and also quantified ventilation heterogeneity.
  
  
  RESULTS
  There were no significant differences in total ventilation volume, ventilation defect volume, ventilation defect percentage, or mean ventilation heterogeneity (repeated-measures analysis of variance, P = .2116, P = .2825, P = .2871, and P = .7265, respectively) in the patients across the four scanning sessions.
  
  
  CONCLUSIONS
  Our results indicate that total ventilation volume, ventilation defect volume, ventilation defect percentage, and mean ventilation heterogeneity as assessed by HP gas MRI in CF patients with stable health are reproducible over time. This repeatability and the technique's capability to provide noninvasive high-resolution data on regional lung function without ionizing radiation make (3)He MRI a potentially useful outcome measure for CF-related clinical trials.
authors.affiliation: Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Brian
authors.initials: B
authors.lastname: O'Sullivan
authors.affiliation: Hyperpolarized Gas MRI Laboratory, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada.
authors.forename: Marcus
authors.initials: M
authors.lastname: Couch
authors.affiliation: Hyperpolarized Gas MRI Laboratory, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada. Electronic address: scienceview@nasw.org.
authors.forename: John P
authors.initials: JP
authors.lastname: Roche
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Ronn
authors.initials: R
authors.lastname: Walvick
authors.affiliation: Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Shaokuan
authors.initials: S
authors.lastname: Zheng
authors.affiliation: Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts.
authors.forename: Dawn
authors.initials: D
authors.lastname: Baker
authors.affiliation: Vertex Pharmaceuticals, Incorporated, Cambridge, Massachusetts.
authors.forename: Mac
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Vertex Pharmaceuticals, Incorporated, Cambridge, Massachusetts.
authors.forename: Martyn
authors.initials: M
authors.lastname: Botfield
authors.affiliation: Hyperpolarized Gas MRI Laboratory, Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada; Department of Chemistry, Lakehead University, Thunder Bay, Ontario, Canada.
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Albert
mesh_terms: D000465:Algorithms; D003550:Cystic Fibrosis / Q000503:physiopathology*; D006371:Helium; D006801:Humans; D007554:Isotopes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D012129:Respiratory Function Tests
chemical_list: D007554:Isotopes; D006371:Helium
keywords: Hyperpolarized gas MRI; cystic fibrosis; functional lung imaging; pulmonary functional imaging; repeatability