Free-breathing Pulmonary 1H and Hyperpolarized 3He MRI: Comparison in COPD and Bronchiectasis

Rationale and Objectives: In this proof-of-concept demonstration, we aimed to quantitatively and qualitatively compare pulmonary ventilation abnormalities derived from Fourier decomposition of free-breathing H-1 magnetic resonance imaging (FDMRI) to hyperpolarized He-3 MRI in subjects with chronic obstructive pulmonary disease (COPD) and bronchiectasis. Materials and 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 He-3 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 He-3 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 He-3 MRI VDP (r = .88; P = .0001), He-3 MRI apparent diffusion coefficient (r = .71; P < .05), airways resistance (r = .60; P < .05), and RA(950) (r = .80; P < .01). In subjects with bronchiectasis, FDMRI VDP (5 +/- 3%) and He-3 MRI VDP (18 +/- 9%) were significantly different (P < .001) and not correlated P>.05). The Dice similarity coefficient (DSC) for FDMRI and He-3 MRI ventilation was 86 +/- 7% for COPD and 86 +/- 4% for bronchiectasis subjects (P>.05); the DSC for FDMRI ventilation defects and CT RA(950) was 19 +/- 20% in COPD and 2 +/- 3% in bronchiectasis subjects (P < .01). Conclusions: FDMRI and He-3 MRI VDP were strongly related in COPD but not in bronchiectasis subjects. In COPD only, FDMRI ventilation defects were spatially related with He-3 ventilation defects and emphysema.