Noninvasive quantification of alveolar morphometry in elderly never- and ex-smokers

Paulin, Gregory; Ouriadov, Alexei; Lessard, Eric; Sheikh, Khadija; McCormack, David G.; Párraga, Grace

doi:10.14814/phy2.12583

Cited by 24 publications

(36 citation statements)

References 53 publications

(108 reference statements)

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“…A small predicted difference between 1.5‐ and 3‐T measurements was recently confirmed by Paulin et al . . However, our estimates of the relative errors for B 0 = 3 T are smaller than those found in ref.…”

Section: Lung Morphometry With Hyperpolarized Gas Diffusion Mri – Thecontrasting

confidence: 82%

Diffusion lung imaging with hyperpolarized gas MRI

2015

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Lung imaging using conventional 1 H MRI presents great challenges due to low density of lung tissue, lung motion and very fast lung tissue transverse relaxation (typical T2* is about 1-2 ms).MRI with hyperpolarized gases ( 3 He and 129 Xe) provides a valuable alternative due to a very strong signal originated from inhaled gas residing in the lung airspaces and relatively slow gas T2* relaxation (typical T2* is about 20-30 ms). Though in vivo human experiments should be done very fast -usually during a single breath-hold. In this review we describe the recent developments in diffusion lung MRI with hyperpolarized gases. We show that a combination of modeling results of gas diffusion in lung airspaces and diffusion measurements with variable diffusion-sensitizing gradients allows extracting quantitative information on the lung microstructure at the alveolar level. This approach, called in vivo lung morphometry, allows from a less than 15-second MRI scan, providing quantitative values and spatial distributions of the same physiological parameters as are measured by means of the "standard" invasive stereology (mean linear intercept, surface-tovolume ratio, density of alveoli, etc.). Besides, the approach makes it possible to evaluate some advanced Weibel parameters characterizing lung microstructure -average radii of alveolar sacs and ducts, as well as the depth of their alveolar sleeves. Such measurements, providing in vivo information on the integrity of pulmonary acinar airways and their changes in different diseases, are of great importance and interest to a broad range of physiologists and clinicians. We also discuss a new type of experiments that are based on the in vivo lung morphometry technique combined with quantitative CT measurements as well as with the Gradient Echo MRI measurements of hyperpolarized gas transverse relaxation in the lung airspaces. Such experiments provide additional information on the blood vessel volume fraction, specific gas volume, the length of acinar airways, and allows evaluation of lung parenchymal and non-parenchymal tissue.

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Section: Lung Morphometry With Hyperpolarized Gas Diffusion Mri – Thecontrasting

confidence: 82%

Diffusion lung imaging with hyperpolarized gas MRI

2015

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“…The SNR of the CS image was generally higher than that of the corresponding FS image. The SNR could affect the anisotropic diffusion coefficient estimations and, consequently, the morphometric parameters . Moreover, the CS reconstruction algorithms could contribute to the differences as well .…”

Section: Discussionmentioning

confidence: 99%

“…The SNR could affect the anisotropic diffusion coefficient estimations and, consequently, the morphometric parameters. 21,41 Moreover, the CS reconstruction algorithms could contribute to the differences as well. 38 The direct comparisons of the CS and FS measurements during a single breath hold indicate that the differences may mainly be attributable to the CS reconstruction.…”

Section: Discussionmentioning

confidence: 99%

Lung morphometry using hyperpolarized ¹²⁹Xe multi‐b diffusion MRI with compressed sensing in healthy subjects and patients with COPD

et al. 2018

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“…A Hann filter was applied to maximize the signal-to-noise ratio of some diffusionweighted images before further processing, as described previously (42).…”

Section: Image Analysismentioning

confidence: 99%

Pulmonary MRI morphometry modeling of airspace enlargement in chronic obstructive pulmonary disease and alpha‐1 antitrypsin deficiency

Ouriadov

Lessard

Sheikh

et al. 2017

Magnetic Resonance in Med

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Purpose: We generated lung morphometry measurements using single-breath diffusion-weighted MRI and three different acinar duct models in healthy participants and patients with emphysema stemming from chronic obstructive lung disease (COPD) and alpha-1 antitrypsin deficiency (AATD). Methods: Single-breath-inhaled 3 He MRI with five diffusion sensitizations (b-value ¼ 0, 1.6, 3.2, 4.8, and 6.4 s/cm 2 ) was used, and signal intensities were fit using a cylindrical and single-compartment acinar-duct model to estimate MRIderived mean linear intercept (L m ) and surface-to-volume ratio (S/V). A stretched exponential model was also developed to estimate the mean airway length and L m . Results: We evaluated 42 participants, including 15 elderly never-smokers (69 6 5 years), 12 ex-smokers without COPD (67 6 11 years), 9 COPD ex-smokers (80 6 6 years), and 6 AATD patients (59 6 6 years). In the never-and ex-smokers, the diffusing capacity of the lung for carbon monoxide (DL CO ) and computed tomography relative area of less than 2950 Hounsfield units (RA 950 ) were normal, but these were abnormal in the COPD and AATD patients, which is reflective of emphysema. Although cylindrical and stretched-exponential-model estimates of L m and S/V were not significantly different, the single-compartment-model estimates were significantly different (P < 0.05) for the never-and ex-smoker subgroups. All models estimated significantly worse L m and S/V in the AATD and COPD subgroups compared with the never-and exsmokers without emphysema. Conclusions: Differences in airspace enlargement may be estimated using L m and S/V, generated using MRI and a stretchedexponential or cylindrical model of the acinar ducts. Magn Reson Med 79:439-448,

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Noninvasive quantification of alveolar morphometry in elderly never- and ex-smokers

Cited by 24 publications

References 53 publications

Diffusion lung imaging with hyperpolarized gas MRI

Diffusion lung imaging with hyperpolarized gas MRI

Lung morphometry using hyperpolarized ¹²⁹Xe multi‐b diffusion MRI with compressed sensing in healthy subjects and patients with COPD

Pulmonary MRI morphometry modeling of airspace enlargement in chronic obstructive pulmonary disease and alpha‐1 antitrypsin deficiency

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Noninvasive quantification of alveolar morphometry in elderly never- and ex-smokers

Cited by 24 publications

References 53 publications

Diffusion lung imaging with hyperpolarized gas MRI

Diffusion lung imaging with hyperpolarized gas MRI

Lung morphometry using hyperpolarized 129Xe multi‐b diffusion MRI with compressed sensing in healthy subjects and patients with COPD

Pulmonary MRI morphometry modeling of airspace enlargement in chronic obstructive pulmonary disease and alpha‐1 antitrypsin deficiency

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Lung morphometry using hyperpolarized ¹²⁹Xe multi‐b diffusion MRI with compressed sensing in healthy subjects and patients with COPD