Analysis of the effect of foreign gases in the production of hyperpolarized gas on a simple system working under atmospheric pressure

Fukutomi, Junko; Suzuki, Eiichi; Shimizu, Tetsuji; Kimura, Atsuomi; Fujiwara, Hideaki

doi:10.1016/s1090-7807(02)00132-5

Cited by 29 publications

(32 citation statements)

References 20 publications

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“…3c for each laser power was achieved when the eŠective laser pass length was the same as the cell length, when the chance of collisional exchange between Rb and 129 Xe was at its highest. Our results support previousˆndings 31,32 that the buŠer gas enhances the polarization of xenon (Fig. 3a) and extend to an in vivo study with statistical analysis of the dissolved phase spectra (Fig.…”

Section: Discussionsupporting

confidence: 92%

“…This signal could not be measured with a small-bore MR system even at 9.4T. 31 This result can be attributable to the amount of gas (60 for up to 1 cm 3 ) in a large-bore system, so the volume eŠect can be expected in future human studies. We did not require oxygen to shorten the T1 for accumulation and did not use the ratio of total spins in the polarized state to that in the Boltzmann state with oxygen in the calculation of the polarization.…”

Section: Discussionmentioning

confidence: 98%

“…The partial pressure ratio of N2 to He wasˆxed at 0.5 in consideration of overall performance 31 and simpliˆcation. The composition of the xenon gas was changed from 3z to 100z to measure buŠer 129 Xe on a 3.0T MRI system with a 55-cm bore (GE Medical System, SIGNA) was developed for this study.…”

Section: Methodsmentioning

confidence: 99%

“…Polarization enhancement with buŠer gases by non-radiative quenching and by spectral broadening has been reported quantitatively. 29,[31][32][33] Increasing the partial pressure of buŠer gases lowers the density of xenon in the blood when mixed gases are inhaled. The xenon in the mixed gases can be condensed at low temperatures while maintaining its polarization [31][32][33] ; however, this requires a complex apparatus.…”

Section: Magnetic Resonance In Medical Sciencesmentioning

confidence: 99%

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Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

et al. 2004

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MRI (magnetic resonance imaging) with 129 Xe has gained much attention as a diagnostic methodology because of its a‹nity for lipids and possible polarization. The quantitative estimation of net detectability and stability of hyperpolarized 129 Xe in the dissolved phase in vivo is valuable to the development of clinical applications. The goal of this study was to develop a stable hyperpolarized 129 Xe experimental 3T system to statistically analyze the dissolved-phase 129 Xe signal in the rat lungs.The polarization of 129 Xe with buŠer gases at the optical pumping cell was measured under adiabatic fast passage against the temperature of an oven and laser absorption at the cell. The gases were insuOEated into the lungs of Sprague-Dawley rats (n＝15, 400-550 g) through an endotracheal tube under spontaneous respiration. Frequency-selective spectroscopy was performed for the gas phase and dissolved phase. We analyzed the 129 Xe signal in the dissolved phase to measure the chemical shift, T 2 * , delay and its ratio in a rat lungs on 3T.The polarizer was able to produce polarized gas (1.1±0.47z, 120 cm 3 ) hundreds of times with the laser absorption ratio (25z) kept constant at the cell. The optimal buŠer gas ratio of 25-50z rendered the maximum signal in the dissolved phase. Two dominant peaks of 211.8±0.9 and 201.1±0.6 ppm were observed with a delay of 0.4±0.9 and 0.9±1.0 s from the gas phase spectra. The ratios of their average signal to that of the gas phase were 5.6±5.2z and 4.4±4.7z, respectively. The T 2 * of the air space in the lungs was 2.5±0.5 ms, which was 3.8 times shorter than that in a syringe.We developed a hyperpolarized 129 Xe experimental system using a 3T MRI scanner that yields su‹cient volume and polarization and quantitatively analyzed the dissolved-phase 129 Xe signal in the rat lungs.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 98%

Section: Methodsmentioning

confidence: 99%

Section: Magnetic Resonance In Medical Sciencesmentioning

confidence: 99%

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Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

et al. 2004

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“…We performed all experiments on a Varian Unity INOVA 400WB with a 9.4T vertical magnet (Varian Technologies Japan Ltd., Tokyo) and utilized a self-shielded imaging probe (Litz coil switchable to 129 Xe, 1 H, and 19 F) of 32-mm diameter equipping an RF coil 15-mm long (Doty Scientiˆc, Columbia, SC, USA).…”

Section: Nmr Methodsmentioning

confidence: 99%

A Simple Method for Quantitative Measurement and Analysis of Hyperpolarized 129Xe Uptake Dynamics in Mouse Brain under Controlled Flow

Kimura

Imai

Wakayama

et al. 2008

MRMS

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We established a simple method for measuring and quantifying uptake dynamics of hyperpolarized (HP) 129 Xe in mouse brain, which includes application of a saturation recovery pulse sequence under controlled ‰ow of HP 129 Xe. The technique allows pursuit of the time-dependent change in 129 Xe nuclear magnetic resonance signal in the uptake process without eŠect from radiofrequency destruction of the polarization and the dynamics in mouse lung. The uptake behavior is well described by a simple model that depends only on a decay rate constant comprising cerebral blood ‰ow and the longitudinal relaxation rate of HP 129 Xe in the brain tissue. The improved analysis enabled precise determination of the decay rate constant as 0.107±0.013 s -1 (±standard deviation, n＝5), leading to estimation of longitudinal relaxation time, T 1i , as 15.3±3.5 s.

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Effect of reduced pressure on the polarization of ¹²⁹Xe in the production of hyperpolarized ¹²⁹Xe gas: Development of a simple continuous flow mode hyperpolarizing system working at pressures as low as 0.15 atm

Imai

Fukutomi

Kimura

et al. 2008

Concepts Magn Reson

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ABSTRACT:The effect of reduced pressure on the polarization of 129 Xe has been examined in batch and continuous flow modes aiming at developing a simple and convenient hyperpolarizing system. The effect of foreign gases was found to show a different tendency at reduced pressure as low as 0.15 atm compared to that near atmospheric pressure. For example, 129 Xe polarization in binary mixtures of Xe and N 2 was larger than that observed in ternary mixtures of Xe, N 2 , and 4 He when compared with the same Xe content, and the highest polarization of 63.6% was given by the 5% Xe þ 95% N 2 mixture in the batch mode. The most noticeable result in the flow mode was that 129 Xe polarization reached a plateau at 0.15 atm when cell pressure was reduced from atmospheric pressure, being enhanced to about twice of that observed near atmospheric pressure. Also demonstrated is the use of isotopically enriched 129 Xe gas at reduced partial pressure. This will be devoid of the anesthetic side effects of Xe while making use of enhanced polarization at reduced pressure, leading to the development of a simple and convenient hyperpolarizing system for medical use.

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Analysis of the effect of foreign gases in the production of hyperpolarized gas on a simple system working under atmospheric pressure

Cited by 29 publications

References 20 publications

Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

A Simple Method for Quantitative Measurement and Analysis of Hyperpolarized 129Xe Uptake Dynamics in Mouse Brain under Controlled Flow

Effect of reduced pressure on the polarization of ¹²⁹Xe in the production of hyperpolarized ¹²⁹Xe gas: Development of a simple continuous flow mode hyperpolarizing system working at pressures as low as 0.15 atm

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Analysis of the effect of foreign gases in the production of hyperpolarized gas on a simple system working under atmospheric pressure

Cited by 29 publications

References 20 publications

Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

Development of a Hyperpolarized 129Xe System on 3T for the Rat Lungs

A Simple Method for Quantitative Measurement and Analysis of Hyperpolarized 129Xe Uptake Dynamics in Mouse Brain under Controlled Flow

Effect of reduced pressure on the polarization of 129Xe in the production of hyperpolarized 129Xe gas: Development of a simple continuous flow mode hyperpolarizing system working at pressures as low as 0.15 atm

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Effect of reduced pressure on the polarization of ¹²⁹Xe in the production of hyperpolarized ¹²⁹Xe gas: Development of a simple continuous flow mode hyperpolarizing system working at pressures as low as 0.15 atm