title: Free-breathing pulmonary 1H and Hyperpolarized 3He MRI: comparison in COPD and bronchiectasis.
abstract: OBJECTIVE
  In this proof-of-concept demonstration, we aimed to quantitatively and qualitatively compare pulmonary ventilation abnormalities derived from Fourier decomposition of free-breathing (1)H magnetic resonance imaging (FDMRI) to hyperpolarized (3)He MRI in subjects with chronic obstructive pulmonary disease (COPD) and bronchiectasis.
  
  
  METHODS
  All subjects provided written informed consent to a protocol approved by a local research ethics board and Health, Canada, and they underwent MRI, computed tomography (CT), spirometry, and plethysmography during a single 2-hour visit. Semiautomated segmentation was used to generate ventilation defect measurements derived from FDMRI and (3)He MRI, and these were compared using analysis of variance and Pearson correlations.
  
  
  RESULTS
  Twenty-six subjects were evaluated including 12 COPD subjects (67 ± 9 years) and 14 bronchiectasis subjects (70 ± 11 years). For COPD subjects, FDMRI and (3)He MRI ventilation defect percent (VDP) was 7 ± 6% and 24 ± 14%, respectively (P < .001; bias = -16 ± 9%). In COPD subjects, FDMRI was significantly correlated with (3)He MRI VDP (r = .88; P = .0001), (3)He MRI apparent diffusion coefficient (r = .71; P < .05), airways resistance (r = .60; P < .05), and RA950 (r = .80; P < .01). In subjects with bronchiectasis, FDMRI VDP (5 ± 3%) and (3)He MRI VDP (18 ± 9%) were significantly different (P < .001) and not correlated (P > .05). The Dice similarity coefficient (DSC) for FDMRI and (3)He MRI ventilation was 86 ± 7% for COPD and 86 ± 4% for bronchiectasis subjects (P > .05); the DSC for FDMRI ventilation defects and CT RA950 was 19 ± 20% in COPD and 2 ± 3% in bronchiectasis subjects (P < .01).
  
  
  CONCLUSIONS
  FDMRI and (3)He MRI VDP were strongly related in COPD but not in bronchiectasis subjects. In COPD only, FDMRI ventilation defects were spatially related with (3)He ventilation defects and emphysema.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7; Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Dante P I
authors.initials: DP
authors.lastname: Capaldi
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7; Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Khadija
authors.initials: K
authors.lastname: Sheikh
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Fumin
authors.initials: F
authors.lastname: Guo
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7; Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Svenningsen
authors.affiliation: Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada.
authors.forename: Roya
authors.initials: R
authors.lastname: Etemad-Rezai
authors.affiliation: James Hogg Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Harvey O
authors.initials: HO
authors.lastname: Coxson
authors.affiliation: James Hogg Research Centre, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Jonathon A
authors.initials: JA
authors.lastname: Leipsic
authors.affiliation: Division of Respirology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada.
authors.forename: David G
authors.initials: DG
authors.lastname: McCormack
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7; Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada; Graduate Program in Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada; Department of Medical Imaging, The University of Western Ontario, London, Ontario, Canada. Electronic address: gparraga@robarts.ca.
authors.forename: Grace
authors.initials: G
authors.lastname: Parraga
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001987:Bronchiectasis / Q000503:physiopathology*; D005260:Female; D006371:Helium; D006801:Humans; D006859:Hydrogen; D007091:Image Processing, Computer-Assisted; D007554:Isotopes; D008168:Lung / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D012119:Respiration; D012129:Respiratory Function Tests / Q000706:statistics & numerical data; D013147:Spirometry
chemical_list: D007554:Isotopes; D006371:Helium; D006859:Hydrogen
keywords: Fourier decomposition; bronchiectasis; chronic obstructive pulmonary disease; magnetic resonance imaging