title: Hyperpolarized 3He and 129Xe MR imaging in healthy volunteers and patients with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  To quantitatively compare hyperpolarized helium 3 (3He) and xenon 129 (129Xe) magnetic resonance (MR) images obtained within 5 minutes in healthy volunteers and patients with chronic obstructive pulmonary disease (COPD) and to evaluate the correlations between 3He and 129Xe MR imaging measurements and those from spirometry and plethysmography.
  
  
  METHODS
  This study was approved by an ethics board and compliant with HIPAA. Written informed consent was obtained from all subjects. Eight healthy volunteers and 10 patients with COPD underwent MR imaging, spirometry, and plethysmography. Ventilation defect percentages (VDPs) at 3He and 129Xe imaging were obtained by using semiautomated segmentation. Apparent diffusion coefficients (ADCs) were calculated from 3He (b=1.6 sec/cm2) and 129Xe (b=12 sec/cm2) diffusion-weighted images. VDPs at hyperpolarized 3He and 129Xe imaging were compared with a two-tailed Wilcoxon signed rank test and analysis of variance; Pearson correlation coefficients were used to evaluate the relationships among measurements.
  
  
  RESULTS
  129Xe VDP was significantly greater than 3He VDP for patients with COPD (P<.0001) but not for healthy volunteers (P=.35), although 3He and 129Xe VDPs showed a significant correlation for all subjects (r=0.91, P<.0001). The forced expiratory volume in 1 second (FEV1) showed a similar and significant correlation with 3He VDP (r=-0.84, P<.0001) and 129Xe VDP (r=-0.89, P<.0001), although the correlation between the FEV1/forced vital capacity (FVC) ratio and 129Xe VDP (r=-0.95, P<.0001) was significantly greater (P=.01) than that for FEV1/FVC and 3He VDP (r=-0.84, P<.0001). A significant correlation was also observed for 3He and 129Xe ADC (r=0.97, P<.0001); 129Xe ADC was significantly correlated with diffusing capacity of lung for carbon monoxide (r=-0.79, P=.03) and computed tomographic emphysema measurements (areas with attenuation values in the 15th percentile: r=-0.91, P=.0003; relative areas with attenuation values of less than -950 HU: r=0.87, P=.001).
  
  
  CONCLUSIONS
  In patients with COPD, the VDP obtained with hyperpolarized 29Xe MR imaging was significantly greater than that with 3He MR imaging, suggesting incomplete or delayed filling of lung regions that may be related to the different properties of 129Xe gas and physiologic and/or anatomic abnormalities in COPD.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Dr, London, ON, Canada N6A 5K8.
authors.forename: Miranda
authors.initials: M
authors.lastname: Kirby
authors.forename: Sarah
authors.initials: S
authors.lastname: Svenningsen
authors.forename: Amir
authors.initials: A
authors.lastname: Owrangi
authors.forename: Andrew
authors.initials: A
authors.lastname: Wheatley
authors.forename: Adam
authors.initials: A
authors.lastname: Farag
authors.forename: Alexei
authors.initials: A
authors.lastname: Ouriadov
authors.forename: Giles E
authors.initials: GE
authors.lastname: Santyr
authors.forename: Roya
authors.initials: R
authors.lastname: Etemad-Rezai
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
authors.forename: David G
authors.initials: DG
authors.lastname: McCormack
authors.forename: Grace
authors.initials: G
authors.lastname: Parraga
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000008:administration & dosage; D000368:Aged; D003287:Contrast Media; D005260:Female; D006371:Helium / Q000008:administration & dosage*; D006801:Humans; D007554:Isotopes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055672:Static Electricity; D014979:Xenon Isotopes / Q000008:administration & dosage*
chemical_list: D000336:Aerosols; D003287:Contrast Media; D007554:Isotopes; D014979:Xenon Isotopes; D006371:Helium