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Preclinical MRI Using Hyperpolarized 129Xe. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238338. [PMID: 36500430 PMCID: PMC9738892 DOI: 10.3390/molecules27238338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022]
Abstract
Although critical for development of novel therapies, understanding altered lung function in disease models is challenging because the transport and diffusion of gases over short distances, on which proper function relies, is not readily visualized. In this review we summarize progress introducing hyperpolarized 129Xe imaging as a method to follow these processes in vivo. The work is organized in sections highlighting methods to observe the gas replacement effects of breathing (Gas Dynamics during the Breathing Cycle) and gas diffusion throughout the parenchymal airspaces (3). We then describe the spectral signatures indicative of gas dissolution and uptake (4), and how these features can be used to follow the gas as it enters the tissue and capillary bed, is taken up by hemoglobin in the red blood cells (5), re-enters the gas phase prior to exhalation (6), or is carried via the vasculature to other organs and body structures (7). We conclude with a discussion of practical imaging and spectroscopy techniques that deliver quantifiable metrics despite the small size, rapid motion and decay of signal and coherence characteristic of the magnetically inhomogeneous lung in preclinical models (8).
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Wakayama T, Ueyama T, Imai F, Kimura A, Fujiwara H. Quantitative assessment of regional lung ventilation in emphysematous mice using hyperpolarized 129Xe MRI with a continuous flow hyperpolarizing system. Magn Reson Imaging 2022; 92:88-95. [PMID: 35654279 DOI: 10.1016/j.mri.2022.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Lung ventilation function in small animals can be assessed by using hyperpolarized gas MRI. For these experiments a free breathing protocol is generally preferred to mechanical ventilation as mechanical ventilation can often lead to ventilation lung injury, while the need to maintain a gas reservoir may lead to a partial reduction of the polarization. PURPOSE To evaluate regional lung ventilation of mice by a simple but fast method under free breathing and give evidence for effectiveness with an elastase instilled emphysematous mice. ANIMAL MODEL Emphysematous mice. MATERIALS AND METHODS A Look-Locker based saturation recovery sequence was developed for continuous flow hyperpolarized (CF-HP) 129Xe gas experiments, and the apparent gas-exchange rate, k', was measured by the analysis of the saturation recovery curve. RESULTS In mice with elastase-induced mild emphysema, reductions of 15-30% in k' values were observed as the results of lesion-induced changes in the lung. DATA CONCLUSION The proposed method was applied to an emphysematous model mice and ventilation dysfunctions have been approved as a definite decrease in k' values, supporting the usefulness for a non-invasive assessment of the lung functions in preclinical study by the CF-HP 129Xe experiments.
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Affiliation(s)
- Tetsuya Wakayama
- Department of Medical Physics and Engineering, Area of Medical Imaging Technology and Science, Division of Health Sciences, Graduate of School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tsuyoshi Ueyama
- Department of Medical Physics and Engineering, Area of Medical Imaging Technology and Science, Division of Health Sciences, Graduate of School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Fumito Imai
- Department of Medical Physics and Engineering, Area of Medical Imaging Technology and Science, Division of Health Sciences, Graduate of School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsuomi Kimura
- Department of Medical Physics and Engineering, Area of Medical Imaging Technology and Science, Division of Health Sciences, Graduate of School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hideaki Fujiwara
- Department of Medical Physics and Engineering, Area of Medical Imaging Technology and Science, Division of Health Sciences, Graduate of School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan.
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Bdaiwi AS, Niedbalski PJ, Hossain MM, Willmering MM, Walkup LL, Wang H, Thomen RP, Ruppert K, Woods JC, Cleveland ZI. Improving hyperpolarized 129 Xe ADC mapping in pediatric and adult lungs with uncertainty propagation. NMR IN BIOMEDICINE 2022; 35:e4639. [PMID: 34729838 PMCID: PMC8828677 DOI: 10.1002/nbm.4639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
RATIONALE Hyperpolarized (HP) 129 Xe-MRI provides non-invasive methods to quantify lung function and structure, with the 129 Xe apparent diffusion coefficient (ADC) being a well validated measure of alveolar airspace size. However, the experimental factors that impact the precision and accuracy of HP 129 Xe ADC measurements have not been rigorously investigated. Here, we introduce an analytical model to predict the experimental uncertainty of 129 Xe ADC estimates. Additionally, we report ADC dependence on age in healthy pediatric volunteers. METHODS An analytical expression for ADC uncertainty was derived from the Stejskal-Tanner equation and simplified Bloch equations appropriate for HP media. Parameters in the model were maximum b-value (bmax ), number of b-values (Nb ), number of phase encoding lines (Nph ), flip angle and the ADC itself. This model was validated by simulations and phantom experiments, and five fitting methods for calculating ADC were investigated. To examine the lower range for 129 Xe ADC, 32 healthy subjects (age 6-40 years) underwent diffusion-weighted 129 Xe MRI. RESULTS The analytical model provides a lower bound on ADC uncertainty and predicts that decreased signal-to-noise ratio yields increases in relative uncertainty (ϵADC) . As such, experimental parameters that impact non-equilibrium 129 Xe magnetization necessarily impact the resulting ϵADC . The values of diffusion encoding parameters (Nb and bmax ) that minimize ϵADC strongly depend on the underlying ADC value, resulting in a global minimum for ϵADC . Bayesian fitting outperformed other methods (error < 5%) for estimating ADC. The whole-lung mean 129 Xe ADC of healthy subjects increased with age at a rate of 1.75 × 10-4 cm2 /s/yr (p = 0.001). CONCLUSIONS HP 129 Xe diffusion MRI can be improved by minimizing the uncertainty of ADC measurements via uncertainty propagation. Doing so will improve experimental accuracy when measuring lung microstructure in vivo and should allow improved monitoring of regional disease progression and assessment of therapy response in a range of lung diseases.
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Affiliation(s)
- Abdullah S. Bdaiwi
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
- Department of Biomedical Engineering, University of
Cincinnati, Cincinnati, OH 45221
| | - Peter J. Niedbalski
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
| | - Md M. Hossain
- Division of Biostatistics and Epidemiology, Cincinnati
Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Matthew M. Willmering
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
| | - Laura L. Walkup
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
- Department of Biomedical Engineering, University of
Cincinnati, Cincinnati, OH 45221
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45221
| | - Hui Wang
- Philips Healthcare, Cincinnati, OH, USA
| | - Robert P. Thomen
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
| | - Kai Ruppert
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
| | - Jason C. Woods
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45221
| | - Zackary I. Cleveland
- Center for Pulmonary Imaging Research, Division of
Pulmonary Medicine, Children’s Hospital Medical Center, Cincinnati, OH
45229
- Department of Biomedical Engineering, University of
Cincinnati, Cincinnati, OH 45221
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH 45221
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Marshall H, Stewart NJ, Chan HF, Rao M, Norquay G, Wild JM. In vivo methods and applications of xenon-129 magnetic resonance. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 122:42-62. [PMID: 33632417 PMCID: PMC7933823 DOI: 10.1016/j.pnmrs.2020.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/26/2020] [Accepted: 11/29/2020] [Indexed: 05/28/2023]
Abstract
Hyperpolarised gas lung MRI using xenon-129 can provide detailed 3D images of the ventilated lung airspaces, and can be applied to quantify lung microstructure and detailed aspects of lung function such as gas exchange. It is sensitive to functional and structural changes in early lung disease and can be used in longitudinal studies of disease progression and therapy response. The ability of 129Xe to dissolve into the blood stream and its chemical shift sensitivity to its local environment allow monitoring of gas exchange in the lungs, perfusion of the brain and kidneys, and blood oxygenation. This article reviews the methods and applications of in vivo129Xe MR in humans, with a focus on the physics of polarisation by optical pumping, radiofrequency coil and pulse sequence design, and the in vivo applications of 129Xe MRI and MRS to examine lung ventilation, microstructure and gas exchange, blood oxygenation, and perfusion of the brain and kidneys.
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Affiliation(s)
- Helen Marshall
- POLARIS, Imaging Sciences, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Neil J Stewart
- POLARIS, Imaging Sciences, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Ho-Fung Chan
- POLARIS, Imaging Sciences, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Madhwesha Rao
- POLARIS, Imaging Sciences, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Graham Norquay
- POLARIS, Imaging Sciences, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Jim M Wild
- POLARIS, Imaging Sciences, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom.
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