title: Detection of age-dependent changes in healthy adult lungs with diffusion-weighted 3He MRI.
abstract: OBJECTIVE
  To investigate changes in lung microstructure in healthy adult subjects with no smoking history using diffusion-weighted 3He MRI.
  
  
  METHODS
  Diffusion magnetic resonance imaging using hyperpolarized helium 3 (3He) was applied to healthy volunteers to explore the dependence of lung microstructural changes with age, reflected by changes in the apparent diffusion coefficient (ADC) of 3He in lung air spaces. Data from three sites (University of Virginia (UVa), N = 25; University of Wisconsin (UW), N = 8; University of Nottingham (UN), N = 11) were combined in pooled analysis, including a total of N = 44 subjects (age range, 18-69 years; average age, 41.7 +/- 16.7 years).
  
  
  RESULTS
  ADC was found to depend on age at all three sites (UW, R = +0.95, P = .0003; UVa, R = +0.74, P < .0001; UN, R = +0.96, P < .0001). Increases in mean ADCs with age appeared similar across sites (UW, +0.0017 cm2 s(-1) y(-1); UVa, +0.0015 cm2 s(-1) y(-1); pooled, +0.0015 cm2 s(-1) y(-1); P = .71). In a regional analysis performed on UW data, the increase in ADC affected all regions of the lung, but the apical and middle regions showed a greater increase compared with the base of the lung.
  
  
  CONCLUSIONS
  Results suggest the observed age dependence of the ADC may be caused by changes in lung microstructure that increase alveolar volume during the aging process.
authors.affiliation: Medical Physics, Department of Radiology, University of Wisconsin Hospital, University of Wisconsin, Madison, WI 53792, USA. fains@mr.radiology.wisc.edu
authors.forename: Sean B
authors.initials: SB
authors.lastname: Fain
authors.forename: Talissa A
authors.initials: TA
authors.lastname: Altes
authors.forename: Shilpa R
authors.initials: SR
authors.lastname: Panth
authors.forename: Michael D
authors.initials: MD
authors.lastname: Evans
authors.forename: Barnaby
authors.initials: B
authors.lastname: Waters
authors.forename: John P
authors.initials: JP
authors.lastname: Mugler
authors.forename: Frank R
authors.initials: FR
authors.lastname: Korosec
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Grist
authors.forename: Mike
authors.initials: M
authors.lastname: Silverman
authors.forename: Michael
authors.initials: M
authors.lastname: Salerno
authors.forename: John
authors.initials: J
authors.lastname: Owers-Bradley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006371:Helium; D006801:Humans; D007554:Isotopes; D008168:Lung / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011653:Pulmonary Diffusing Capacity
chemical_list: D007554:Isotopes; D006371:Helium