title: Hyperpolarized 3He magnetic resonance imaging of ventilation defects in healthy elderly volunteers: initial findings at 3.0 Tesla.
abstract: OBJECTIVE
  Hyperpolarized (3)He magnetic resonance imaging ventilation defects have been observed in subjects with respiratory disorders. We quantified (3)He ventilation defects in elderly and middle-aged subjects who had no history of smoking, respiratory, or cardiovascular disorders.
  
  
  METHODS
  Hyperpolarized (3)He magnetic resonance imaging ventilation defect volume (VDV) and ventilation defect score (VDS) were assessed in eight elderly healthy volunteers (mean 67+/-6 years) scanned twice within 7+/-2 minutes and again 7+/-2 days later. A younger cohort of 24 subjects (mean 44+/-10 years) was also scanned for direct comparison. Four observers blinded to scan timepoint and subject identity scored VDS and manually segmented VDV in all center coronal slices.
  
  
  RESULTS
  Center coronal slice ventilation defects were observed in six of eight elderly subjects (ages 63-74 years, 5 males) in all scans acquired and in no middle-aged subjects. At the scan timepoint, mean VDS was 2.7 (mean VDV 52+/-34 cm(3)), whereas for same-day rescan, mean VDS was 2.5 (mean VDV 53+/-35 cm(3)) and at 7-day rescan, mean VDS was 3.6 (mean VDV 48+/-39 cm(3)). Interscan coefficients of variation (COV) for mean VDV was 1.8% (same-day rescan) and 5.3% (7-day rescan) and interobserver COV ranged from 10-12%.
  
  
  CONCLUSIONS
  Elderly subjects have ventilation defects that are reproducible in same-day scanning and 7-day scanning visits. The observation of reproducible pulmonary ventilation defects in otherwise healthy elderly volunteers suggests caution must be used in interpreting results from (3)He studies of elderly subjects.
authors.affiliation: The Lawson Health Research Institute, London, ON, Canada. gep@imaging.robarts.ca
authors.forename: Grace
authors.initials: G
authors.lastname: Parraga
authors.forename: Lindsay
authors.initials: L
authors.lastname: Mathew
authors.forename: Roya
authors.initials: R
authors.lastname: Etemad-Rezai
authors.forename: David G
authors.initials: DG
authors.lastname: McCormack
authors.forename: Giles E
authors.initials: GE
authors.lastname: Santyr
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006371:Helium; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007554:Isotopes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012123:Pulmonary Ventilation / Q000502:physiology*; D015203:Reproducibility of Results; D013147:Spirometry
chemical_list: D007554:Isotopes; D006371:Helium