Quantitative measurement of regional lung ventilation using <sup>3</sup>He MRI

Deninger, A.; Månsson, Sven; Petersson, Johan; Pettersson, Göran; Magnusson, Peter; Svensson, Jonas; Fridlund, Björn; Hansson, Georg; Erjefeldt, Ingrid; Wollmer, Per; Golman, Klaes

doi:10.1002/mrm.10206

Cited by 145 publications

(156 citation statements)

References 25 publications

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“…[3] above as [4] In terms of the structure of length L, we express the overall diffusivity LRDC using eqn. [3] in the same way, [5] Equating the two expression for the flux J, we obtain [6] This result is correct when the LRDC so determined is much smaller than the gas free diffusion, D 0 . Using the above values of D W and s and setting L = 600 μm and x = 6 μm, reasonable estimates for acinar airways (27), we obtain LRDC = 10 −4 cm 2 /s.…”

Section: Permeation Through Airway Wallsmentioning

confidence: 54%

“…Overall, the diffusion through the structure of Figure 3 can be regarded as several processes in series, so the overall diffusivity is no larger than the result of eqn. [6]. We conclude that this mechanism is negligible, as a result of the low solubility of 3 He in water and its slow diffusion in water.…”

Section: Permeation Through Airway Wallsmentioning

confidence: 78%

“…We note that eqn. [6] was derived using a linear concentration (or spin magnetization) variation along x, but the result is fully general for length scales longer than L.…”

Section: Permeation Through Airway Wallsmentioning

confidence: 99%

“…Subsequently, dynamic 3 He MRI was used to show the time evolution of gas distribution, with sub-second time resolution (4,5). A quantitative method for measurement of the local fractional ventilation (the fraction of gas replaced with each breath) has also appeared (6). The local oxygen concentration and its decrease during breath hold have been determined (7,8) from the 3 He T 1 , allowing the local ventilation -perfusion ratio to be calculated (9).…”

Section: Introductionmentioning

confidence: 99%

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The Role of Collateral Paths in Long-range Diffusion of 3He in Lungs

et al. 2008

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Rationale and Objectives-The hyperpolarized 3 He long-range diffusion coefficient (LRDC) in lungs is sensitive to changes in lung structure due to emphysema, reflecting the increase in collateral paths resulting from tissue destruction. However, no clear understanding of LRDC in healthy lungs has emerged. Here we compare LRDC measured in healthy lungs with computer simulations of diffusion along the airway tree with no collateral connections.Materials and Methods-Computer simulations of diffusion of spatially modulated spin magnetization were performed in computer generated, symmetric-branching models of lungs and compared with existing LRDC measurements in canine and human lungs.Results-The simulations predict LRDC values of order 0.001 cm 2 /s, approximately 20 times smaller than the measured LRDC. We consider and rule out possible mechanisms for LRDC not included in the simulations: incomplete breath hold, cardiac motion, and passage of dissolved 3 He through airway walls. However, a very low density of small (micron) holes in the airways is shown to account for the observed LRDC.Conclusion-It is proposed that LRDC in healthy lungs is determined by small collateral pathways.

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Section: Permeation Through Airway Wallsmentioning

confidence: 54%

Section: Permeation Through Airway Wallsmentioning

confidence: 78%

“…We note that eqn. [6] was derived using a linear concentration (or spin magnetization) variation along x, but the result is fully general for length scales longer than L.…”

Section: Permeation Through Airway Wallsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Role of Collateral Paths in Long-range Diffusion of 3He in Lungs

et al. 2008

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“…Although in obstructive lung diseases, ventilation measures correlate well with FEV 1 (68,73), and correlate spatially with regions of decreased parenchymal density on CT for patients and smokers with COPD and BO syndrome in lung transplant (71,76), little progress has been made toward quantifying the gradations of signal density to true quantitative ventilation. Quantitation has been achieved in respiratory-gated images in small animals (77), but it remains a challenge for the gas volumes and limited scan times in human disease.…”

Section: Ventilation Imaging (Spin Density)mentioning

confidence: 99%

Functional lung imaging using hyperpolarized gas MRI

Fain

Korosec

Holmes

et al. 2007

Magnetic Resonance Imaging

178

158

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The noninvasive assessment of lung function using imaging is increasingly of interest for the study of lung diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Hyperpolarized gas MRI (HP MRI) has demonstrated the ability to detect changes in ventilation, perfusion, and lung microstructure that appear to be associated with both normal lung development and disease progression. The physical characteristics of HP gases and their application to MRI are presented with an emphasis on current applications. Clinical investigations using HP MRI to study asthma, COPD, cystic fibrosis, pediatric chronic lung disease, and lung transplant are reviewed. Recent advances in polarization, pulse sequence development for imaging with Xe-129, and prototype low magnetic field systems dedicated to lung imaging are highlighted as areas of future development for this rapidly evolving technology.

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Aerosols and gaseous contrast agents for magnetic resonance imaging of the lung

Mosbah

Ruíz-Cabello

Berthezène

et al. 2008

Contrast Media & Molecular

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Magnetic resonance imaging of lungs and the investigation of pulmonary pathologies with this technique are limited by low proton spin density, degraded magnetic homogeneity and motion. Inhaled contrast agents (gases or aerosols) can improve the diagnostic value of MRI for lung. Paramagnetic contrast agents such as gadolinium chelates aerosol or dioxygen gas increase the relaxivity of proton in lung parenchyma and can be used to assess the ventilated fraction of the bronchoalveolar space. Similarly, inhalation of non proton-MRI nuclei such as perfluorinated gas or hyperpolarized gases ((3)He or (129)Xe) can provide functional ventilation image. In this review paper, the principles, the practical implementation, the limitations and possible safety issues of these different techniques are summarized. The main pre-clinical and clinical applications of these approaches based on oral contrast agents are reviewed and illustrated with cutting-edge lung MRI studies.

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Quantitative measurement of regional lung ventilation using ³He MRI

Abstract: A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (

Cited by 145 publications

References 25 publications

The Role of Collateral Paths in Long-range Diffusion of 3He in Lungs

The Role of Collateral Paths in Long-range Diffusion of 3He in Lungs

Functional lung imaging using hyperpolarized gas MRI

Aerosols and gaseous contrast agents for magnetic resonance imaging of the lung

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Quantitative measurement of regional lung ventilation using 3He MRI

Abstract: A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (

Cited by 145 publications

References 25 publications

The Role of Collateral Paths in Long-range Diffusion of 3He in Lungs

The Role of Collateral Paths in Long-range Diffusion of 3He in Lungs

Functional lung imaging using hyperpolarized gas MRI

Aerosols and gaseous contrast agents for magnetic resonance imaging of the lung

Contact Info

Product

Resources

About

Quantitative measurement of regional lung ventilation using ³He MRI