title: Pulmonary 3He magnetic resonance imaging of childhood asthma.
abstract: BACKGROUND
  Magnetic resonance imaging (MRI) with (3)He does not require ionizing radiation and has been shown to detect regional abnormalities in lung ventilation and structure in adults with asthma, but the method has not been extended to children with asthma. Measurements of regional lung ventilation and microstructure in subjects with childhood asthma could advance our understanding of disease mechanisms.
  
  
  OBJECTIVE
  We sought to determine whether (3)He MRI in children can identify abnormalities related to the diagnosis of asthma or prior history of respiratory illness.
  
  
  METHODS
  Forty-four children aged 9 to 10 years were recruited from a birth cohort at increased risk of asthma and allergic diseases. For each subject, a time-resolved 3-dimensional image series and a 3-dimensional diffusion-weighted image were acquired in separate breathing maneuvers. The numbers and sizes of ventilation defects were scored, and regional maps and statistics of average (3)He diffusion lengths were calculated.
  
  
  RESULTS
  Children with mild-to-moderate asthma had lower average root-mean-square diffusion length (X(rms)) values (P = .004), increased regional SD of diffusion length values (P = .03), and higher defect scores (P = .03) than those without asthma. Children with histories of wheezing illness with rhinovirus infection before the third birthday had lower X(rms) values (P = .01) and higher defect scores (P = .05).
  
  
  CONCLUSIONS
  MRI with (3)He detected more and larger regions of ventilation defect and a greater degree of restricted gas diffusion in children with asthma compared with those seen in children without asthma. These measures are consistent with regional obstruction and smaller and more regionally variable dimensions of the peripheral airways and alveolar spaces.
authors.affiliation: Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wis 53705, USA.
authors.forename: Robert V
authors.initials: RV
authors.lastname: Cadman
authors.forename: Robert F
authors.initials: RF
authors.lastname: Lemanske
authors.forename: Michael D
authors.initials: MD
authors.lastname: Evans
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Jackson
authors.forename: James E
authors.initials: JE
authors.lastname: Gern
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Sorkness
authors.forename: Sean B
authors.initials: SB
authors.lastname: Fain
mesh_terms: D001249:Asthma / Q000473:pathology*; D002648:Child; D005260:Female; D006371:Helium / Q000737:chemistry; D006801:Humans; D007554:Isotopes / Q000737:chemistry; D008168:Lung / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012123:Pulmonary Ventilation; D012135:Respiratory Sounds / Q000503:physiopathology
chemical_list: D007554:Isotopes; D006371:Helium