title: Quantitative (1)H and hyperpolarized (3)He magnetic resonance imaging: comparison in chronic obstructive pulmonary disease and healthy never-smokers.
abstract: OBJECTIVE
  The aim of this study was to quantitatively evaluate the relationship between short echo time pulmonary (1)H magnetic resonance imaging (MRI) signal intensity (SI) and (3)He MRI apparent diffusion coefficients (ADC), high-resolution computed tomography (CT) measurements of emphysema, and pulmonary function measurements.
  
  
  METHODS
  Nine healthy never-smokers and 11 COPD subjects underwent same-day plethysmography, spirometry, short echo time ((TE)=1.2ms) (1)H and diffusion-weighted hyperpolarized (3)He MRI (b=1.6s/cm(2)) at 3.0T. In addition, for COPD subjects only, CT densitometry was also performed.
  
  
  RESULTS
  Mean (1)H SI was significantly greater for never-smokers (12.1 ± 1.1 arbitrary units (AU)) compared to COPD subjects (10.9 ± 1.3 AU, p=0.04). The (1)H SI AP-gradient was also significantly greater for never-smokers (0.40 AU/cm, R(2)=0.94) compared to COPD subjects (0.29 AU/cm, R(2)=0.968, p=0.05). There was a significant correlation between (1)H SI and (3)He ADC (r=-0.58, p=0.008) and significant correlations between (1)H MR SI and CT measurements of emphysema (RA950, r=-0.69, p=0.02 and HU15, r=0.66, p=0.03).
  
  
  CONCLUSIONS
  The significant and moderately strong relationship between (1)H SI and (3)He ADC, as well as between (1)H SI and CT measurements of emphysema suggests that these imaging methods and measurements may be quantifying similar tissue changes in COPD and that pulmonary (1)H SI may be used to monitor emphysema as a complement to CT and noble gas MRI.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Canada. Electronic address: aowrangi@robats.ca.
authors.forename: Amir M
authors.initials: AM
authors.lastname: Owrangi
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8; Applied Science Laboratories, General Electric Healthcare, Canada. Electronic address: jxwang@robats.ca.
authors.forename: Jian X
authors.initials: JX
authors.lastname: Wang
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8. Electronic address: awheat@imaging.robarts.ca.
authors.forename: Andrew
authors.initials: A
authors.lastname: Wheatley
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8; Division of Respirology, Department of Medicine, The University of Western Ontario, London, Canada. Electronic address: David.Mccormack@lhsc.on.ca.
authors.forename: David G
authors.initials: DG
authors.lastname: McCormack
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Canada N6A 5K8; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Canada; Department of Medical Imaging, The University of Western Ontario, London, Canada; Department of Medical Biophysics, The University of Western Ontario, London, Canada. Electronic address: gparraga@robats.ca.
authors.forename: Grace
authors.initials: G
authors.lastname: Parraga
mesh_terms: D000368:Aged; D003287:Contrast Media; D005260:Female; D006371:Helium; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011522:Protons; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis*; D011656:Pulmonary Emphysema / Q000175:diagnosis* / Q000209:etiology; D012016:Reference Values; D015203:Reproducibility of Results; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D012907:Smoking; D055672:Static Electricity
chemical_list: D003287:Contrast Media; D011522:Protons; D006371:Helium