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Lung morphometry using hyperpolarized 129 Xe apparent diffusion coefficient anisotropy in chronic obstructive pulmonary disease
Author(s) -
Ouriadov Alexei,
Farag Adam,
Kirby Miranda,
McCormack David G.,
Parraga Grace,
Santyr Giles E.
Publication year - 2013
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24595
Subject(s) - copd , fractional anisotropy , nuclear medicine , diffusion mri , effective diffusion coefficient , nuclear magnetic resonance , lung , medicine , pulmonary disease , anisotropy , diffusion , chemistry , magnetic resonance imaging , radiology , physics , optics , thermodynamics
Purpose The goal of this work was to investigate lung morphological changes associated with chronic obstructive pulmonary disease (COPD) using hyperpolarized 129 Xe diffusion‐weighted MRI. Methods Hyperpolarized 129 Xe MRI was performed at three different nonzero diffusion sensitizations ( b ‐value = 12, 20, and 30 s/cm 2 ) in the lungs of four subjects with COPD and four healthy volunteers. The image signal intensities were fit as a function of b ‐value to obtain anisotropic diffusion coefficient maps for all subjects. The image signal intensities were also fit to a morphological model allowing extraction of length scales associated with the terminal airways: external radius ( R ), internal radius ( r ), mean airspace chord length ( L m ), and depth of alveolar sleeve ( h ). Results Longitudinal ( D L ) and transverse ( D T ) anisotropic diffusion coefficients were both significantly increased (both P = 0.004) in the COPD subjects (0.102 ± 0.02 cm 2 /s and 0.072 ± 0.02 cm 2 /s, respectively) compared with the healthy subjects (0.083 ± 0.011 cm 2 /s and 0.046 ± 0.017 cm 2 /s, respectively). Significant morphological differences were observed between the COPD subjects and healthy volunteers, specifically decreases in h (68 ± 36 µm vs. 95 ± 710 µm, respectively, P = 0.019) and increases in L m (352 ± 57 µm vs. 253 ± 37 µm, respectively, P = 0.002) consistent with values obtained previously using hyperpolarized 3 He MRI in similar subjects. Conclusions Diffusion‐weighted hyperpolarized 129 Xe MRI is a promising technique for mapping changes in human lung morphology and may be useful for early detection of emphysema associated with COPD. Magn Reson Med 70:1699–1706, 2013. © 2013 Wiley Periodicals, Inc.