Lung morphometry using hyperpolarized <sup>129</sup>Xe apparent diffusion coefficient anisotropy in chronic obstructive pulmonary disease

Ouriadov, Alexei; Farag, Adam; Kirby, Miranda; McCormack, David G.; Párraga, Grace; Santyr, Giles

doi:10.1002/mrm.24595

Cited by 64 publications

(112 citation statements)

References 48 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…was confirmed in vivo by experimental measurements in humans , canines , mice , and rats using hyperpolarized 3 He gas. It was also recently confirmed in humans and rats using hyperpolarized 129 Xe gas. Example of the data obtained by Jacob et al from a rat for a broad range of b ‐values up to 40 s/cm 2 is shown in Figure where the authors compared fitting their data to the model in Eq.…”

Section: In Vivo Lung Morphometry Techniquementioning

confidence: 77%

See 1 more Smart Citation

Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results

Yablonskiy

Sukstanskiı̆

Quirk

et al. 2013

Magnetic Resonance in Med

View full text Add to dashboard Cite

The introduction of hyperpolarized gases ( 3 He and 129 Xe) has opened the door to applications for which gaseous agents are uniquely suited-lung MRI. One of the pulmonary applications, diffusion MRI, relies on measuring Brownian motion of inhaled hyperpolarized gas atoms diffusing in lung airspaces. In this article we provide an overview of the theoretical ideas behind hyperpolarized gas diffusion MRI and the results obtained over the decade-long research. We describe a simple technique based on measuring gas apparent diffusion coefficient (ADC) and an advanced technique, in vivo lung morphometry, that quantifies lung microstructure both in terms of Weibel parameters (acinar airways radii and alveolar depth) and standard metrics (mean linear intercept, surface-to-volume ratio, and alveolar density) that are widely used by lung researchers but were previously available only from invasive lung biopsy. This technique has the ability to provide unique three-dimensional tomographic information on lung microstructure from a less than 15 s MRI scan with results that are in good agreement with direct histological measurements. These safe and sensitive diffusion measurements improve our understanding of lung structure and functioning in health and disease, providing a platform for monitoring the efficacy of therapeutic interventions in clinical trials. Approximately 12 million Americans suffer from chronic obstructive pulmonary diseases (COPD) including chronic bronchitis and emphysema as well as asthma. It is the fourth leading cause of chronic morbidity and mortality in the United States, and is projected to rank fifth in 2020 in burden of disease caused worldwide, according to a study published by the World Bank/World Health Organization (1). Numerous diagnostic tools have been developed to evaluate the presence and the stage of these diseases. The traditional classification for the severity of COPD is based on measurements of airflow limitation during forced expiration (1). Each stage is characterized by the volume of air that can be forcibly exhaled in 1 s (FEV 1 ) and by the ratio of FEV 1 to the forced vital capacity (FVC). Abnormalities in these tests reflect both the reduction in the force available to drive air out of the lung as a result of emphysematous lung destruction (2) and obstruction to airflow in the smaller conducting airways (3-5). However, the specific pathophysiologic role and contribution of emphysema and small airways abnormalities in expiratory airflow obstruction in COPD has been under debate (6,7). While the role of pathologic changes in small airways has received much attention in recent years (8-10), the early-emphysema component of COPD has not. Conventional pulmonary function tests are insensitive to the onset and initial stages of emphysema (11); the same is valid for conventional chest radiography (12). X-ray CT has substantially greater value for evaluation of emphysema (13); there, enlargement of airspaces and destruction of alveolar walls reduces X-ray attenuation and allows the dete...

show abstract

Section: In Vivo Lung Morphometry Techniquementioning

confidence: 77%

“…The first 129 Xe applications of in vivo lung morphometry technique have been demonstrated by Ruppert et al (see example in Fig. ) and Ouriadov et al in humans, and Boudreau et al , and Hegarty et al in rats.…”

Section: In Vivo Lung Morphometry Techniquementioning

confidence: 97%

Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results

Yablonskiy

Sukstanskiı̆

Quirk

et al. 2013

Magnetic Resonance in Med

View full text Add to dashboard Cite

show abstract

“…The L m was calculated using Equation [12], and as shown in Equation [20], S/V was directly proportional to ADC. Finally, S/V 0 was generated using Equation [21] as follows:…”

Section: Stretched-exponential Modelmentioning

confidence: 99%

“…Importantly, estimates may also be generated for the mean linear intercept (L m ) and surface-to-volume ratio (S/V) (16), both welldescribed in the lung stereology literature (17). Previous work also established the relationship of lung MRI and histological measurements (16,(18)(19)(20), and evaluated emphysema patients (16,21), rodent models (18,20), lung cancer (22), and lung aging (23,24). In contrast, a singlecompartment model, as shown in Figure 1b, was also previously used to explain fluid diffusion in porous media (25) and to model 129 Xe (26), 19 F (27), and simulated inhaled-gas diffusion (28) in emphysematous tissue (29).…”

Section: Introductionmentioning

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

Self Cite

View full text Add to dashboard Cite

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,

show abstract

“…Because of these limitations, attention is turning to other gases such as 129Xe gas. [77][78][79][80] Although this agent is more abundant and less expensive, several technical challenges must be overcome before its role in the evaluation of emphysema can be properly understood. 80 Other potential agents include oxygen, Carbon-13 and perflouropropane.…”

Section: Mrimentioning

confidence: 99%

Progress in Imaging COPD, 2004 - 2014

Lynch¹

2014

J COPD F

View full text Add to dashboard Cite

Abbreviations: computed tomography, CT; magnetic resonance imaging, MRI; positron emission tomography, PET; Global Initiative for chronic Obstructive Lung Disease, GOLD; quantitative CT, QCT; Hounsfield Units, HU; percentage of low attenuation area, %LAA; relative area of lung less than -950 HU, RA950; Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints, ECLIPSE; forced expiratory volume in 1 second, FEV1; forced vital capacity, FVC. Journal of the COPD Foundation(GOLD) stage may have substantial, little, or no emphysema. Discrete subphenotypes of COPD include emphysema of varying morphologic appearance, large airway abnormality and small airway obstruction. Increasing awareness of the heterogeneity of COPD has led to increased use of CT to characterize COPD for purposes of genetic evaluation and identification of specific subgroups which may be amenable to therapeutic trials. 1-3 While visual assessment is important in determining the presence and character of emphysema, the last decade has been characterized by increasing use of quantitative imaging to provide precise estimates of the severity and distribution of emphysema, gas trapping and airway wall thickening. Several large cohorts of cigarette smokers have now been quite extensively characterized by CT, resulting in increased knowledge of the clinical correlates of quantitative CT parameters. [4][5][6] The purpose of this paper is to present the substantial contribution that imaging has made to our understanding of COPD over the past 10 years. AbstractComputed tomography (CT) has contributed substantially to our understanding of COPD over the past decade. Visual and quantitative assessments of CT in COPD are complementary. Visual assessment should provide assessment of centrilobular, panlobular and paraseptal emphysema, airway wall thickening, bronchiectasis, findings of respiratory bronchiolitis, and enlargement of the pulmonary artery. Quantitative CT permits evaluation of severity of emphysema, airway wall thickening, and expiratory air trapping, and is now being used for longitudinal evaluation of the progression of COPD. Innovative techniques are being developed to use CT to characterize the pattern of emphysema and smoking-related respiratory bronchiolitis. Magnetic resonance imaging (MRI) and positron emission tomography PET-CT are useful research tools in the evaluation of COPD.

show abstract

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

Abstract: 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.

Cited by 64 publications

References 48 publications

Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results

Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results

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

Progress in Imaging COPD, 2004 - 2014

Contact Info

Product

Resources

About

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

Abstract: 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.

Cited by 64 publications

References 48 publications

Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results

Probing lung microstructure with hyperpolarized noble gas diffusion MRI: theoretical models and experimental results

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

Progress in Imaging COPD, 2004 - 2014

Contact Info

Product

Resources

About

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