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Lung morphometry using hyperpolarized 129Xe apparent diffusion coefficient anisotropy in chronic obstructive pulmonary disease

Authors

  • Alexei Ouriadov,

    1. Ph.D., Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
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  • Adam Farag,

    1. Ph.D., Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
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  • Miranda Kirby,

    1. Ph.D., Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
    2. Department of Medical Biophysics, Western University, London, Ontario, Canada
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  • David G. McCormack,

    1. Department of Medicine, Western University, London, Ontario, Canada
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  • Grace Parraga,

    1. Ph.D., Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
    2. Department of Medical Biophysics, Western University, London, Ontario, Canada
    3. Department of Medical Imaging, Western University, London, Ontario, Canada
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  • Giles E. Santyr

    Corresponding author
    1. Ph.D., Imaging Research Laboratories, Robarts Research Institute, Western University, London, Ontario, Canada
    2. Department of Medical Biophysics, Western University, London, Ontario, Canada
    3. Department of Medical Imaging, Western University, London, Ontario, Canada
    • Correspondence to: Giles E. Santyr, Imaging Research Laboratories, Robarts Research Institute, 100 Perth Drive, London, Ontario ON N6A 5K8, Canada. (E-mail: gsantyr@robarts.ca)

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Abstract

Purpose

The goal of this work was to investigate lung morphological changes associated with chronic obstructive pulmonary disease (COPD) using hyperpolarized 129Xe diffusion-weighted MRI.

Methods

Hyperpolarized 129Xe MRI was performed at three different nonzero diffusion sensitizations (b-value = 12, 20, and 30 s/cm2) 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 (Lm), and depth of alveolar sleeve (h).

Results

Longitudinal (DL) and transverse (DT) anisotropic diffusion coefficients were both significantly increased (both P= 0.004) in the COPD subjects (0.102 ± 0.02 cm2/s and 0.072 ± 0.02 cm2/s, respectively) compared with the healthy subjects (0.083 ± 0.011 cm2/s and 0.046 ± 0.017 cm2/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 Lm (352 ± 57 µm vs. 253 ± 37 µm, respectively, P = 0.002) consistent with values obtained previously using hyperpolarized 3He MRI in similar subjects.

Conclusions

Diffusion-weighted hyperpolarized 129Xe 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.

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