Small Animal Imaging with Hyperpolarized 129Xe Magnetic Resonance

Imai, Hirohiko; Kimura, Atsuomi; Fujiwara, Hideaki

doi:10.2116/analsci.30.157

Cited by 12 publications

(12 citation statements)

References 55 publications

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“…129 Xe chemical shifts have been studied extensively in vitro to examine the interaction of 129 Xe with cells and blood (4,(6)(7)(8)(9)(10). With the advent of hyperpolarization, it has become possible to characterize shifts in mice (11)(12)(13)(14)(15), rats (3,8,16,17), and humans (18)(19)(20)(21). Across these species, four 129 Xe resonances have been reported within the thorax: airspaces (À5 to 10 ppm), aqueous media (195-199 ppm), red blood cells (mouse, 199-200 ppm; rat, 210-213 ppm; human, 216-221 ppm), and adipose tissue (189-194 ppm).…”

Section: Introductionmentioning

confidence: 99%

Establishing an accurate gas phase reference frequency to quantify¹²⁹Xe chemical shifts in vivo

et al. 2016

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Purpose 129Xe interacts with biological media to exhibit chemical shifts exceeding 200 ppm that report on physiology and pathology. Extracting this functional information requires shifts to be measured precisely. Historically, shifts have been reported relative to the gas-phase resonance originating from pulmonary airspaces. However, this frequency is not fixed—it is affected by bulk magnetic susceptibility, as well as Xe-N2, Xe-Xe, and Xe-O2 interactions. Here, we address this by introducing a robust method to determine the 0 ppm 129Xe reference from in vivo data. Methods Respiratory-gated hyperpolarized 129Xe spectra from the gas- and dissolved-phases were acquired in 4 mice at 2T from multiple axial slices within the thoracic cavity. Complex spectra were then fitted in the time domain to identify peaks. Results Gas-phase 129Xe exhibited two distinct resonances corresponding to 129Xe in conducting airways (varying from −0.6±0.2 to +1.3±0.3 ppm) and alveoli (relatively stable, at −2.2±0.1 ppm). Dissolved-phase 129Xe exhibited five reproducible resonances in the thorax at 198.4±0.4, 195.5±0.4, 193.9±0.2, 191.3±0.2, and 190.7±0.3 ppm. Conclusion The alveolar 129Xe resonance exhibits a stable frequency across all mice. Therefore, it can provide a reliable in vivo reference frequency by which to characterize other spectroscopic shifts.

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Section: Introductionmentioning

confidence: 99%

Establishing an accurate gas phase reference frequency to quantify¹²⁹Xe chemical shifts in vivo

et al. 2016

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“…There have been substantial advances in functional pulmonary MRI in the last few decades from imaging gases dominated by polarized noble gases and from tissue MRI, notably from the effect of breathing pure oxygen on the tissue T 1 . The present study is anatomical in comparison.…”

Section: Introductionmentioning

confidence: 96%

“…To be certain we are not missing signal, we have used free induction decay (FID)-projection imaging (as in 11,[20][21][22] dubbed ZTE, for "zero echo time" 23 ) with acquisition times appropriate for the T * 2 calculated from the 8 ppm line width. 21 There have been substantial advances in functional pulmonary MRI in the last few decades from imaging gases 24 dominated by polarized noble gases [25][26][27][28][29][30][31] and from tissue MRI, notably from the effect of breathing pure oxygen on the tissue T 1 . [32][33][34][35][36][37][38][39][40] The present study is anatomical in comparison.…”

Section: Introductionmentioning

confidence: 99%

T₁, T₁ contrast, and Ernst‐angle images of four rat‐lung pathologies

Kuethe

Hix

Fredenburgh

2018

Magnetic Resonance in Med

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Purpose To initiate the archive of relaxation‐weighted images that may help discriminate between pulmonary pathologies relevant to acute respiratory distress syndrome. MRI has the ability to distinguish pathologies by providing a variety of different contrast mechanisms. Lungs have historically been difficult to image with MRI but image quality is sufficient to begin cataloging the appearance of pathologies in T1‐ and T2‐weighted images. This study documents T1 and the use of T1 contrast with four experimental rat lung pathologies. Methods Inversion‐recovery and spoiled steady state images were made at 1.89 T to measure T1 and document contrast in rats with atelectasis, lipopolysaccharide‐induced inflammation, ventilator‐induced lung injury (VILI), and injury from saline lavage. Higher‐resolution Ernst‐angle images were made to see patterns of lung infiltrations. Results T1‐weighted images showed minimal contrast between pathologies, similar to T1‐weighted images of other soft tissues. Images taken shortly after magnetization inversion and displayed with inverted contrast highlight lung pathologies. Ernst‐angle images distinguish the effects of T1 relaxation and spin density and display distinctive patterns. T1 for pathologies were: atelectasis, 1.25 ± 0.046 s; inflammation from instillation of lipopolysaccharide, 1.24 ± 0.015 s; VILI, 1.55 ± 0.064 s (p = 0.0022 vs. normal lung); and injury from saline lavage, 1.90±0.080 s (p = 0.0022 vs. normal lung; p = 0.0079 vs. VILI). T1 of normal lung and erector spinae muscle were 1.25 ± 0.028 s and 1.02 ± 0.027 s, respectively (p = 0.0022). Conclusions Traditional T1‐weighting is subtle. However, images made with inverted magnetization and inverted contrast highlight the pathologies and Ernst‐angle images aid in distinguishing pathologies.

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Section: Introductionmentioning

confidence: 99%

“…MRI and MRS of hyperpolarized noble gases such as 3 He (HP He) and 129 Xe (HP Xe) have developed over the past two decades and become promising methods to investigate lung and brain diseases in preclinical as well as clinical studies. [1][2][3][4][5][6][7] In recent years, despite the advantages of HP He MRI, the developments in HP Xe MRI have become particularly important, because it can address the worldwide scarcity of 3 He. 3 Moreover, HP Xe has many attractive features; for example, Xe exhibits NMR signals at around 0 ppm from 129 Xe gas residing in the lung airspace and at around 200 ppm from 129 Xe dissolved in tissue and blood.…”

Section: Introductionmentioning

confidence: 99%

Hyperpolarized ¹²⁹Xe MRI using isobutene as a new quenching gas

et al. 2016

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The use of a quenching gas, isobutene, with a low vapor pressure was investigated to enhance the utility of hyperpolarized (129) Xe (HP Xe) MRI. Xenon mixed with isobutene was hyperpolarized using a home-built apparatus for continuously producing HP Xe. The isobutene was then readily liquefied and separated almost totally by continuous condensation at about 173 K, because the vapor pressure of isobutene (0.247 kPa) is much lower than that of Xe (157 kPa). Finally, the neat Xe gas was continuously delivered to mice by spontaneous inhalation. The HP Xe MRI was enhanced twofold in polarization level and threefold in signal intensity when isobutene was adopted as the quenching gas instead of N2 . The usefulness of the HP Xe MRI was verified by application to pulmonary functional imaging of spontaneously breathing mice, where the parameters of fractional ventilation (ra ) and gas exchange (fD ) were evaluated, aiming at future extension to preclinical studies. This is the first application of isobutene as a quenching gas for HP Xe MRI.

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Small Animal Imaging with Hyperpolarized 129Xe Magnetic Resonance

Cited by 12 publications

References 55 publications

Establishing an accurate gas phase reference frequency to quantify¹²⁹Xe chemical shifts in vivo

Establishing an accurate gas phase reference frequency to quantify¹²⁹Xe chemical shifts in vivo

T₁, T₁ contrast, and Ernst‐angle images of four rat‐lung pathologies

Hyperpolarized ¹²⁹Xe MRI using isobutene as a new quenching gas

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Small Animal Imaging with Hyperpolarized 129Xe Magnetic Resonance

Cited by 12 publications

References 55 publications

Establishing an accurate gas phase reference frequency to quantify129Xe chemical shifts in vivo

Establishing an accurate gas phase reference frequency to quantify129Xe chemical shifts in vivo

T1, T1 contrast, and Ernst‐angle images of four rat‐lung pathologies

Hyperpolarized 129Xe MRI using isobutene as a new quenching gas

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Product

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Establishing an accurate gas phase reference frequency to quantify¹²⁹Xe chemical shifts in vivo

Establishing an accurate gas phase reference frequency to quantify¹²⁹Xe chemical shifts in vivo

T₁, T₁ contrast, and Ernst‐angle images of four rat‐lung pathologies

Hyperpolarized ¹²⁹Xe MRI using isobutene as a new quenching gas