Dataset Information

Longitudinal nuclear spin relaxation of ¹²⁹ Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.

ABSTRACT:

Purpose

To measure dissolved-phase ¹²⁹ Xe T₁ values at high and low magnetic fields and the field dependence of ¹²⁹ Xe depolarization by hollow fiber membranes used to infuse hyperpolarized xenon in solution.

Methods

Dissolved-phase T₁ measurements were made at 11.7T and 2.1 mT by bubbling xenon in solution and by using a variable delay to allow spins to partially relax back to thermal equilibrium before probing their magnetization. At high field, relaxation values were compared to those obtained by using the small flip angle method. For depolarization studies, we probed the magnetization of the polarized gas diffusing through an exchange membrane module placed at different field strengths.

Results

Total loss of polarization was observed for xenon diffusing through hollow fiber membranes at low field, while significant polarization loss (>20%) was observed at magnetic fields up to 2T. Dissolved-phase ¹²⁹ Xe T₁ values were found consistently shorter at 2.1 mT compared to 11.7T. In addition, both O₂ and Xe gas concentrations in solution were found to significantly affect dissolved-phase ¹²⁹ Xe T₁ values.

Conclusion

Dissolved-phase ¹²⁹ Xe measurements are feasible at low field, but to assess the feasibility of in vivo dissolved-phase imaging and spectroscopy the T₁ of xenon in blood will need to be measured. Both O₂ and Xe concentrations in solution are found to greatly affect dissolved-phase ¹²⁹ Xe T₁ values and may explain, along with RF miscalibration, the large discrepancy in previously reported results.

SUBMITTER: Bryden N

PROVIDER: S-EPMC9420755 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature

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Publications

Longitudinal nuclear spin relaxation of <sup>129</sup> Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.

Bryden Nicholas N McHugh Christian T CT Kelley Michele M Branca Rosa T RT

Magnetic resonance in medicine 20220620 5

<h4>Purpose</h4>To measure dissolved-phase <sup>129</sup> Xe T<sub>1</sub> values at high and low magnetic fields and the field dependence of <sup>129</sup> Xe depolarization by hollow fiber membranes used to infuse hyperpolarized xenon in solution.<h4>Methods</h4>Dissolved-phase T<sub>1</sub> measurements were made at 11.7T and 2.1 mT by bubbling xenon in solution and by using a variable delay to allow spins to partially relax back to thermal equilibrium before probing their magnetization. At h ...[more]

PMID: 35726363

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Project description:Background129 Xe gas-transfer MRI provides regional measures of pulmonary gas exchange in adults and separates xenon in interstitial lung tissue/plasma (barrier) from xenon in red blood cells (RBCs). The technique has yet to be demonstrated in pediatric populations or conditions.Purpose/hypothesisTo perform an exploratory analysis of 129 Xe gas-transfer MRI in children.Study typeProspective.PopulationSeventy-seven human volunteers (38 males, age = 17.7 ± 15.1 years, range 5-68 years, 16 healthy). Four pediatric disease cohorts.Field strength/sequence3-T, three-dimensional-radial one-point Dixon Fast Field Echo (FFE) Ultrashort Echo Time (UTE).AssessmentBreath hold compliance was assessed by quantitative signal-to-noise and dynamic metrics. Whole-lung means and standard deviations were extracted from gas-transfer maps. Gas-transfer metrics were investigated with respect to age and lung disease. Clinical pulmonary function tests were retrospectively acquired for reference lung disease severity.Statistical testsWilcoxon rank-sum tests to compare age and disease cohorts, Wilcoxon signed-rank tests to compare pre- and post-breath hold vitals, Pearson correlations between age and gas-transfer metrics, and limits of normal with a binomial exact test to compare fraction of subjects with abnormal gas-transfer. P ≤ 0.05 was considered significant.ResultsEighty percentage of pediatric subjects successfully completed 129 Xe gas-transfer MRI. Gas-transfer parameters differed between healthy children and adults, including ventilation (0.75 and 0.67) and RBC:barrier ratio (0.31 and 0.46) which also correlated with age (ρ = -0.76, 0.57, respectively). Bone marrow transplant subjects had impaired ventilation (90% of reference) and increased dissolved 129 Xe standard deviation (242%). Bronchopulmonary dysplasia subjects had decreased barrier-uptake (69%). Cystic fibrosis subjects had impaired ventilation (91%) and increased RBC-transfer (146%). Lastly, childhood interstitial lung disease subjects had increased ventilation heterogeneity (113%). Limits of normal provided detection of abnormalities in additional gas-transfer parameters.Data conclusionPediatric 129 Xe gas-transfer MRI was adequately successful and gas-transfer metrics correlated with age. Exploratory analysis revealed abnormalities in a variety of pediatric obstructive and restrictive lung diseases.Level of evidence2 TECHNICAL EFFICACY STAGE: 2.

Project description:It is inferred that magnesian non-porphyritic chondrules in the CB (Bencubbin-type) carbonaceous chondrites formed in an impact generated plume of gas and melt at 4562.49 ± 0.21 Ma (Bollard et al., 2015) and could be suitable for the absolute age normalization of relative chronometers. Here xenon isotopic compositions of neutron irradiated chondrules from the CB chondrites Gujba and Hammadah al Hamra (HH) 237 have been analyzed in an attempt to determine closure time of their I-Xe isotope systematics. One of the HH 237 chondrules, #1, yielded a well-defined I-Xe isochron that corresponds to a closure time of 0.29 ± 0.16 Ma after the Shallowater aubrite standard. Release profiles and diffusion properties of radiogenic 129*Xe and 128*Xe, extracted from this chondrule by step-wise pyrolysis, indicate presence of two iodine host phases with distinct activation energies of 73 and 120 kcal/mol. In spite of the activation energy differences, the I-Xe isotope systematics of these two phases closed simultaneously, suggesting rapid heating and cooling (possibly quenching) of the CB chondrules. The release profiles of U-fission Xe and I-derived Xe correlate in the high temperature host phase supporting simultaneous closure of 129I-129Xe and 207Pb-206Pb systematics. The absolute I-Xe age of Shallowater standard is derived from the observed correlation between I-Xe and Pb-Pb ages in a number of samples. It is re-evaluated here using Pb-Pb ages adjusted for an updated 238U/235U ratio of 137.794 and meteorite specific U-isotope ratios. With the addition of the new data for HH 237 chondrule #1, the re-evaluated absolute I-Xe age of Shallowater is 4562.4 ± 0.2 Ma. The absolute I-Xe age of the HH 237 chondrule #1 is 4562.1 ± 0.3 Ma, in good agreement with U-corrected Pb-Pb ages of the Gujba chondrules (Bollard et al., 2015) and HH 237 silicates (Krot et al., 2005). All I-Xe data used here, and in previous estimates of the absolute age of Shallowater, are calculated using 15.7 ± 0.6 Ma value for 129I half-life. The slopes of I-Xe - Pb-Pb correlation lines plotted for different sets of samples for Shallowater normalization are always ≤1. Assuming uranium half-life values are correct; this restricts the half-life of 129I to ≤15.7 Ma.

Dataset Information

Longitudinal nuclear spin relaxation of ¹²⁹ Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.

Purpose

Methods

Results

Conclusion

Publications

Longitudinal nuclear spin relaxation of <sup>129</sup> Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Longitudinal nuclear spin relaxation of 129 Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.

Purpose

Methods

Results

Conclusion

Publications

Longitudinal nuclear spin relaxation of <sup>129</sup> Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Longitudinal nuclear spin relaxation of ¹²⁹ Xe in solution and in hollow fiber membranes at low and high magnetic field strengths.