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Puddu C, Rao M, Xu X, Deppe MH, Collier G, Maunder A, Chan HF, De Zanche N, Robb F, Wild JM. An asymmetrical whole-body birdcage RF coil without RF shield for hyperpolarized 129 Xe lung MR imaging at 1.5 T. Magn Reson Med 2021; 86:3373-3381. [PMID: 34268802 DOI: 10.1002/mrm.28915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 06/15/2021] [Accepted: 06/15/2021] [Indexed: 11/10/2022]
Abstract
PURPOSE This study describes the development and testing of an asymmetrical xenon-129 (129 Xe) birdcage radiofrequency (RF) coil for 129 Xe lung ventilation imaging at 1.5 Tesla, which allows proton (1 H) system body coil transmit-receive functionality. METHODS The 129 Xe RF coil is a whole-body asymmetrical elliptical birdcage constructed without an outer RF shield to enable 1 H imaging. B 1 + field homogeneity and flip angle mapping of the 129 Xe birdcage RF coil and 1 H system body RF coil with the 129 Xe RF coil in situ were evaluated in the MR scanner. The functionality of the 129 Xe birdcage RF coil was demonstrated through hyperpolarized 129 Xe lung ventilation imaging with the birdcage in both transceiver configuration and transmit-only configuration when combined with an 8-channel 129 Xe receive-only RF coil array. The functionality of 1 H system body coil with the 129 Xe RF coil in situ was demonstrated by acquiring coregistered 1 H lung anatomical MR images. RESULTS The asymmetrical birdcage produced a homogeneous B 1 + field (±10%) in agreement with electromagnetic simulations. Simulations indicated an optimal detuning configuration with 4 diodes. The obtained g-factor of 1.4 for acceleration factor of R = 2 indicates optimal array configuration. Coregistered 1 H anatomical images from the system body coil along with 129 Xe lung images demonstrated concurrent and compatible arrangement of the RF coils. CONCLUSION A large asymmetrical birdcage for homogenous B 1 + transmission with high sensitivity reception for 129 Xe lung MRI at 1.5 Tesla has been demonstrated. The unshielded asymmetrical birdcage design enables 1 H structural lung MR imaging in the same exam.
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Affiliation(s)
- Claudio Puddu
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Madhwesha Rao
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Xiaojun Xu
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Martin H Deppe
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Guilhem Collier
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Adam Maunder
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Ho-Fung Chan
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
| | - Nicola De Zanche
- Department of Medical Physics, Cross Cancer Institute and University of Alberta, Alberta, Canada
| | - Fraser Robb
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom.,GE Healthcare, Aurora, Ohio, USA
| | - Jim M Wild
- POLARIS, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
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Virgincar RS, Robertson SH, Nouls J, Degan S, Schrank GM, He M, Driehuys B. Establishing an accurate gas phase reference frequency to quantify 129 Xe chemical shifts in vivo. Magn Reson Med 2016; 77:1438-1445. [PMID: 27059646 DOI: 10.1002/mrm.26229] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/25/2022]
Abstract
PURPOSE 129 Xe 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. In this study, we addressed this by introducing a robust method to determine the 0 ppm 129 Xe reference from in vivo data. METHODS Respiratory-gated hyperpolarized 129 Xe spectra from the gas- and dissolved-phases were acquired in four 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 129 Xe exhibited two distinct resonances corresponding to 129 Xe 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 129 Xe 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 129 Xe 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. Magn Reson Med 77:1438-1445, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Rohan S Virgincar
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Scott H Robertson
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
| | - John Nouls
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Radiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Simone Degan
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Center for Molecular and Biomolecular Imaging, Duke University Medical Center, Durham, North Carolina, USA
| | - Geoffry M Schrank
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Radiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Mu He
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Electrical and Computer Engineering, Duke University, Durham North Carolina, USA
| | - Bastiaan Driehuys
- Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina, USA.,Biomedical Engineering, Duke University, Durham, North Carolina, USA.,Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA.,Radiology, Duke University Medical Center, Durham, North Carolina, USA
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Witte C, Schröder L. NMR of hyperpolarised probes. NMR IN BIOMEDICINE 2013; 26:788-802. [PMID: 23033215 DOI: 10.1002/nbm.2873] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 07/23/2012] [Accepted: 08/29/2012] [Indexed: 06/01/2023]
Abstract
Increasing the sensitivity of NMR experiments is an ongoing field of research to help realise the exquisite molecular specificity of this technique. Hyperpolarisation of various nuclei is a powerful approach that enables the use of NMR for molecular and cellular imaging. Substantial progress has been achieved over recent years in terms of both tracer preparation and detection schemes. This review summarises recent developments in probe design and optimised signal encoding, and promising results in sensitive disease detection and efficient therapeutic monitoring. The different methods have great potential to provide molecular specificity not available by other diagnostic modalities.
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Affiliation(s)
- Christopher Witte
- ERC Project BiosensorImaging, Leibniz-Institut für Molekulare Pharmakologie, Berlin, Germany
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Iguchi S, Imai H, Hori Y, Nakajima J, Kimura A, Fujiwara H. Direct imaging of hyperpolarized 129Xe alveolar gas uptake in a mouse model of emphysema. Magn Reson Med 2012; 70:207-15. [PMID: 22887860 DOI: 10.1002/mrm.24452] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 06/27/2012] [Accepted: 07/11/2012] [Indexed: 01/07/2023]
Abstract
MRI of hyperpolarized (129)Xe dissolved in pulmonary tissues, and blood has the potential to offer a new tool for regional evaluation of pulmonary gas exchange and perfusion; however, the extremely short T2* and low magnetization density make it difficult to acquire the image. In this study, an ultrashort echo-time sequence was introduced, and its feasibility to quantitatively assess emphysema-like pulmonary tissue destruction by a combination of dissolved- and gas-phase (129)Xe lung MRI was investigated. The ultrashort echo-time has made it possible to acquire dissolved (129)Xe images with reasonably high spatial resolution of 0.625 × 0.625 mm(2) and to obtain T2* of 0.67 ± 0.30 ms in a spontaneously breathing mouse at 9.4 T. The regional dynamic alveolar gas uptake as well as subsequent transport by pulmonary blood flow was also visualized. The ratio of (129)Xe magnetization that diffused into the septa relative to the gas-phase magnetization F was regionally evaluated. The mean F value of elastase-treated mice was 2.28 ± 0.46%, which was significantly reduced from that of control mice 3.41 ± 0.48% (P = 0.0052). This reflects the reduced uptake efficiency due to alveolar tissue destruction and is correlated with the histologically derived alveolar surface-to-volume ratio.
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Affiliation(s)
- Satoshi Iguchi
- Department of Medical Physics and Engineering, Division of Health Sciences, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
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Imai H, Kimura A, Akiyama K, Ota C, Okimoto K, Fujiwara H. Development of a fast method for quantitative measurement of hyperpolarized 129Xe dynamics in mouse brain. NMR IN BIOMEDICINE 2012; 25:210-217. [PMID: 21755553 DOI: 10.1002/nbm.1733] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 05/31/2023]
Abstract
A fast method has been established for the precise measurement and quantification of the dynamics of hyperpolarized (HP) xenon-129 ((129)Xe) in the mouse brain. The key technique is based on repeatedly applying radio frequency (RF) pulses and measuring the decrease of HP (129)Xe magnetization after the brain Xe concentration has reached a steady state due to continuous HP (129)Xe ventilation. The signal decrease of the (129)Xe nuclear magnetic resonance (NMR) signal was well described by a simple theoretical model. The technique made it possible to rapidly evaluate the rate constant α, which is composed of cerebral blood flow (CBF), the partition coefficient of Xe between the tissue and blood (λ(i)), and the longitudinal relaxation time (T(1i)) of HP (129)Xe in the brain tissue, without any effect of depolarization by RF pulses and the dynamics in the lung. The technique enabled the precise determination of α as 0.103 ± 0.018 s(-1) (± SD, n = 5) on healthy mice. To investigate the potential of this method for detecting physiological changes in the brain of a kainic acid (KA) -induced mouse model of epilepsy, an attempt was made to follow the time course of α after KA injection. It was found that the α value changes characteristically with time, reflecting the change in the physiological state of the brain induced by KA injection. By measuring CBF using (1)H MRI and (129)Xe dynamics simultaneously and comparing these results, it was suggested that the reduction of T(1i), in addition to the increase of CBF due to KA-induced epilepsy, are possible causes of the change in (129)Xe dynamics. Thus, the present method would be useful to detect a pathophysiological state in the brain and provide a novel tool for future brain study.
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Affiliation(s)
- Hirohiko Imai
- Department of Medical Physics and Engineering, Area of Medical Technology and Science, Division of Health Sciences, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan
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