In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

Bidinosti, Christopher; Choukeife, J.; Nacher, Pierre-Jean; Tastevin, Geneviève

doi:10.1016/s1090-7807(02)00198-2

Cited by 56 publications

(80 citation statements)

References 34 publications

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“…The radii of alveoli range from approximately 0.12 to 0.18 mm (10,11) in humans to approximately 0.05 mm alveolar radius in rats (12). The duct size in humans range from 0.22 to 0.60 mm, depending on the generation (10), up to three times the size of an alveoli radius.…”

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confidence: 99%

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Boudreau

Ouriadov

et al. 2011

Magnetic Resonance in Med

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Hyperpolarized 3 He gas can provide detailed anatomical maps of the macroscopic airways in the lungs (i.e., ventilation) as well as insight into the lung microstructure through the apparent diffusion coefficient. In particular, the apparent diffusion coefficient of 3 He in the lung exhibits anisotropic effects that depend on diffusion time (d), and it has been shown to be extraordinarily sensitive to enlargement in terminal airways and alveoli associated with emphysema. In this study, the anisotropic nature of the 3 He apparent diffusion coefficient is studied in a rat model of emphysema, based on elastase instillation, specifically for d values less than one millisecond. Hyperpolarized helium 3 ( 3 He) MR imaging can provide both anatomical and functional information that may be important for diagnosing lung diseases. One of the most interesting implementations of 3 He imaging is diffusionweighted MR imaging, taking advantage of the much larger apparent diffusion coefficient (ADC) of 3 He compared to 1.1 Â 10 À5 cm 2 /s for hydrogen ( 1 H). 3 He diffusion in the lungs is restricted by airway and alveolar walls and therefore is highly dependent on lung microstructure. Diffusion measurements are sensitive to lung morphological information such as airway sizes and surface to volume ratio, by measuring the ADC that is largely dependent on lung geometry (1). This enables the tracking of disease progression, such as human chronic obstructive pulmonary disease (1,2) and asthma in mouse models (3). 3 He ADC has been shown to be sensitive to changes in terminal airway anatomy, specifically alveolar damage due to emphysema in both humans (1,4-6) and animal models (3,7-9).The lungs branch off from the trachea to bronchi, bronchioles, and eventually terminate at the alveolar sacs after approximately 25 divisions. The radii of alveoli range from approximately 0.12 to 0.18 mm (10,11) in humans to approximately 0.05 mm alveolar radius in rats (12). The duct size in humans range from 0.22 to 0.60 mm, depending on the generation (10), up to three times the size of an alveoli radius. In this geometry, diffusion is highly restricted for 3 He nuclei as the diffusion lengthis about 0.6 mm given a diffusion time (d) of 1.8 ms, which is typical of diffusion-weighted MR imaging. D 0 in Eq. 1 is the free diffusion coefficient and is equal to 1.91 Â 10 À4 m 2 /s (11) for pure 3 He at room temperature and 0.88 cm 2 /s when diluted in air. It has been shown that 3 He ADC obtained at millisecond diffusion times can distinguish normal from emphysematous tissue and correlates with mean linear intercept histology, an accepted measure of alveolar damage (12,13). 3 He ADC values obtained at sub-millisecond diffusion times (14) are expected to be even more sensitive to emphysema, especially in small animals. At longer diffusion times on the order of seconds, 3 He ADC is expected to reflect changes in lung anatomy over much larger length scales on the order of centimetres. Recent work has demonstrated ADC sensitivity to collateral pathway changes...

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confidence: 99%

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Boudreau

Ouriadov

et al. 2011

Magnetic Resonance in Med

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“…, where the binary-diffusion coefficient is given by D 3−N 2 =0.811×(T /300) 1.65 cm 2 /s [20,22]. This yields D=1.10 cm 2 /s for the gas mixtures used in this work (x=0.5, T =20 • C).…”

Section: Theoretical Considerationsmentioning

confidence: 83%

“…The tipping rf field was generated by a pair of saddle-shaped coils, an exact 1:4 reduced-scale copy of the whole-body B 1 coils described in ref. [20]. The good rf field homogeneity (checked to be better than 1% over the samples), combined with long spoiling times (100 ms) between successive encoding steps, ensured a uniform decay of the magnetisation with the repeated rf pulses.…”

Section: Experimental System and Methodsmentioning

confidence: 98%

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Achieving high spatial resolution and high SNR in low-field MRI of hyperpolarised gases with Slow Low Angle SHot

Safiullin¹,

Talbot²,

Nacher³

2013

Journal of Magnetic Resonance

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MRI of hyperpolarised gases is usually performed with fast data acquisition to achieve high spatial resolutions despite rapid diffusion-induced signal attenuation. We describe a double-cross k-space sampling scheme suitable for slow low angle shot (SLASH) acquisition and yielding an increased SNR. It consists of a series of anisotropic partial acquisitions with a reduced resolution in the read direction, which alleviates signal attenuation and still provides a high isotropic resolution. The advantages of SLASH imaging over conventional FLASH imaging are evaluated analytically, using numerical lattice calculations, and experimentally in phantom cells filled with hyperpolarised 3 He-N2 gas mixtures. Low-field MRI is performed (here 2.7 mT), a necessary condition to obtain long T * 2 values in lungs for slow acquisition. Two additional benefits of the SLASH scheme over FLASH imaging have been demonstrated: it is less sensitive to the artefacts due to concomitant gradients and it allows measuring apparent diffusion coefficients for an extended range of times.

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“…2 holds true, which motivates the application of low magnetic field strength systems to perform HNG studies of p A O 2 using R 2,CPMG (6,(25)(26)(27)(28). CPMG spin-spin relaxation rate measurements of hyperpolarized 3 He at a field strength of 3 mT have recently been performed in human lungs (26) with corresponding T 2 relaxation times of sec. This work demonstrated the feasibility of measuring p A O 2 in vivo using spin-spin relaxation rates measured with a CPMG pulse sequence at very low magnetic field strength.…”

Section: Introductionmentioning

confidence: 99%

Measurement of alveolar oxygen partial pressure in the rat lung using Carr‐Purcell‐Meiboom‐Gill spin–spin relaxation times of hyperpolarized ³He and ¹²⁹Xe at 74 mT

Kraayvanger

Bidinosti

Dominguez‐Viqueira

et al. 2010

Magnetic Resonance in Med

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Regional measurement of alveolar oxygen partial pressure can be obtained from the relaxation rates of hyperpolarized noble gases, 3 He and 129 Xe, in the lungs. Recently, it has been demonstrated that measurements of alveolar oxygen partial pressure can be obtained using the spin-spin relaxation rate (R 2 ) of 3 He at low magnetic field strengths (<0.1 T) in vivo. R 2 measurements can be achieved efficiently using the Carr-Purcell-Meiboom-Gill pulse sequence. In this work, alveolar oxygen partial pressure measurements based on Carr-PurcellMeiboom-Gill R 2 values of hyperpolarized 3 He and 129 Xe in vitro and in vivo in the rat lung at low magnetic field strength (74 mT) are presented. In vitro spin-spin relaxivity constants for 3 He and 129 Xe were determined to be (5.2 6 0.6) 310 26 Pa 21 sec 21 and (7.3 6 0.4) 310 26 Pa 21 s 21 compared with spin-lattice relaxivity constants of (4.0 6 0.4) 310 26 Pa 21 s 21 and (4.3 6 1.3) 3 10 26 Pa 21 s 21 , respectively. In vivo experimental measurements of alveolar oxygen partial pressure using 3 He in whole rat lung show good agreement (r 2 5 0.973) with predictions based on lung volumes and ventilation parameters. For 129 Xe, multicomponent relaxation was observed with one component exhibiting an increase in R 2 with decreasing alveolar oxygen partial pressure. Magn Reson Med 64:1484-1490,

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In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

Cited by 56 publications

References 34 publications

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Achieving high spatial resolution and high SNR in low-field MRI of hyperpolarised gases with Slow Low Angle SHot

Measurement of alveolar oxygen partial pressure in the rat lung using Carr‐Purcell‐Meiboom‐Gill spin–spin relaxation times of hyperpolarized ³He and ¹²⁹Xe at 74 mT

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In vivo NMR of hyperpolarized 3He in the human lung at very low magnetic fields

Cited by 56 publications

References 34 publications

Mapping of 3He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Mapping of 3He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Achieving high spatial resolution and high SNR in low-field MRI of hyperpolarised gases with Slow Low Angle SHot

Measurement of alveolar oxygen partial pressure in the rat lung using Carr‐Purcell‐Meiboom‐Gill spin–spin relaxation times of hyperpolarized 3He and 129Xe at 74 mT

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Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Mapping of ³He apparent diffusion coefficient anisotropy at sub‐millisecond diffusion times in an elastase‐instilled rat model of emphysema

Measurement of alveolar oxygen partial pressure in the rat lung using Carr‐Purcell‐Meiboom‐Gill spin–spin relaxation times of hyperpolarized ³He and ¹²⁹Xe at 74 mT