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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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2
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Shepelytskyi Y, Grynko V, Rao MR, Li T, Agostino M, Wild JM, Albert MS. Hyperpolarized 129 Xe imaging of the brain: Achievements and future challenges. Magn Reson Med 2022; 88:83-105. [PMID: 35253919 PMCID: PMC9314594 DOI: 10.1002/mrm.29200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/22/2021] [Accepted: 01/25/2022] [Indexed: 11/25/2022]
Abstract
Hyperpolarized (HP) xenon-129 (129 Xe) brain MRI is a promising imaging modality currently under extensive development. HP 129 Xe is nontoxic, capable of dissolving in pulmonary blood, and is extremely sensitive to the local environment. After dissolution in the pulmonary blood, HP 129 Xe travels with the blood flow to the brain and can be used for functional imaging such as perfusion imaging, hemodynamic response detection, and blood-brain barrier permeability assessment. HP 129 Xe MRI imaging of the brain has been performed in animals, healthy human subjects, and in patients with Alzheimer's disease and stroke. In this review, the overall progress in the field of HP 129 Xe brain imaging is discussed, along with various imaging approaches and pulse sequences used to optimize HP 129 Xe brain MRI. In addition, current challenges and limitations of HP 129 Xe brain imaging are discussed, as well as possible methods for their mitigation. Finally, potential pathways for further development are also discussed. HP 129 Xe MRI of the brain has the potential to become a valuable novel perfusion imaging technique and has the potential to be used in the clinical setting in the future.
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Affiliation(s)
- Yurii Shepelytskyi
- Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada.,Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada
| | - Vira Grynko
- Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada.,Chemistry and Materials Science Program, Lakehead University, Thunder Bay, Ontario, Canada
| | - Madhwesha R Rao
- POLARIS, Unit of Academic Radiology, Department of IICD, University of Sheffield, Sheffield, UK
| | - Tao Li
- Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada
| | - Martina Agostino
- Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada
| | - Jim M Wild
- POLARIS, Unit of Academic Radiology, Department of IICD, University of Sheffield, Sheffield, UK.,Insigneo Institute for in Silico Medicine, Sheffield, UK
| | - Mitchell S Albert
- Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada.,Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada.,Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada
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3
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Friedlander Y, Zanette B, Lindenmaier A, Li D, Kadlecek S, Santyr G, Kassner A. Hyperpolarized 129 Xe MRI of the rat brain with chemical shift saturation recovery and spiral-IDEAL readout. Magn Reson Med 2021; 87:1971-1979. [PMID: 34841605 DOI: 10.1002/mrm.29105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 01/03/2023]
Abstract
PURPOSE To demonstrate the feasibility of 129 Xe chemical shift saturation recovery (CSSR) combined with spiral-IDEAL imaging for simultaneous measurement of the time-course of red blood cell (RBC) and brain tissue signals in the rat brain. METHODS Images of both the RBC and brain tissue 129 Xe signals from the brains of five rats were obtained using interleaved spiral-IDEAL imaging following chemical shift saturation pulses applied at multiple CSSR delay times, τ. A linear fit of the signals to τ was used to calculate the slope of the signal for both RBC and brain tissue compartments on a voxel-by-voxel basis. Gas transfer was evaluated by measuring the ratio of the whole brain tissue-to-RBC signal intensities as a function of τ. To investigate the relationship between the CSSR images and gas transfer in the brain, the experiments were repeated during hypercapnic ventilation. RESULTS Hypercapnia, affected the ratio of the tissue-to-RBC signal intensity (p = 0.026), consistent with an increase in gas transfer. CONCLUSION CSSR with spiral-IDEAL imaging is feasible for acquisition of 129 Xe RBC and brain tissue time-course images in the rat brain. Differences in the time-course of the signal intensity ratios are consistent with gas transfer changes expected under hypercapnic conditions.
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Affiliation(s)
- Yonni Friedlander
- Translational Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Brandon Zanette
- Translational Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andras Lindenmaier
- Translational Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Li
- Translational Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Giles Santyr
- Translational Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Andrea Kassner
- Translational Medicine Program, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
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4
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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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5
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Mazzanti ML, Walvick RP, Zhou X, Sun Y, Shah N, Mansour J, Gereige J, Albert MS. Distribution of hyperpolarized xenon in the brain following sensory stimulation: preliminary MRI findings. PLoS One 2011; 6:e21607. [PMID: 21789173 PMCID: PMC3137603 DOI: 10.1371/journal.pone.0021607] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 06/03/2011] [Indexed: 11/18/2022] Open
Abstract
In hyperpolarized xenon magnetic resonance imaging (HP (129)Xe MRI), the inhaled spin-1/2 isotope of xenon gas is used to generate the MR signal. Because hyperpolarized xenon is an MR signal source with properties very different from those generated from water-protons, HP (129)Xe MRI may yield structural and functional information not detectable by conventional proton-based MRI methods. Here we demonstrate the differential distribution of HP (129)Xe in the cerebral cortex of the rat following a pain stimulus evoked in the animal's forepaw. Areas of higher HP (129)Xe signal corresponded to those areas previously demonstrated by conventional functional MRI (fMRI) methods as being activated by a forepaw pain stimulus. The percent increase in HP (129)Xe signal over baseline was 13-28%, and was detectable with a single set of pre and post stimulus images. Recent innovations in the production of highly polarized (129)Xe should make feasible the emergence of HP (129)Xe MRI as a viable adjunct method to conventional MRI for the study of brain function and disease.
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Affiliation(s)
- Mary L. Mazzanti
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ronn P. Walvick
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xin Zhou
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Yanping Sun
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Lurie Family Imaging Center, Center for Biomedical Imaging in Oncology, Dana Farber Cancer Institute, Massachusetts, United States of America
| | - Niral Shah
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Joey Mansour
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica Gereige
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mitchell S. Albert
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Thunder Bay Regional Research Institute, Thunder Bay, Ontario, Canada
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6
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Zhou X, Sun Y, Mazzanti M, Henninger N, Mansour J, Fisher M, Albert M. MRI of stroke using hyperpolarized 129Xe. NMR IN BIOMEDICINE 2011; 24:170-175. [PMID: 20821723 DOI: 10.1002/nbm.1568] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 04/20/2010] [Accepted: 04/21/2010] [Indexed: 05/26/2023]
Abstract
Because there is no background signal from xenon in biological tissue, and because inhaled xenon is delivered to the brain by blood flow, we would expect a perfusion deficit, such as is seen in stroke, to reduce the xenon concentration in the region of the deficit. Thermal polarization yields negligible xenon signal relative to hyperpolarized xenon; therefore, hyperpolarized xenon can be used as a tracer of cerebral blood flow. Using a rat permanent right middle cerebral artery occlusion model, we demonstrated that hyperpolarized (129)Xe MRI is able to detect, in vivo, the hypoperfused area of focal cerebral ischemia, that is the ischemic core area of stroke. To the best of our knowledge, this is the first time that hyperpolarized (129)Xe MRI has been used to explore normal and abnormal cerebral perfusion. Our study shows a novel application of hyperpolarized (129)Xe MRI for imaging stroke, and further demonstrates its capacity to serve as a complementary tool to proton MRI for the study of the pathophysiology during brain hypoperfusion.
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Affiliation(s)
- Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China.
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7
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Abstract
Hyperpolarized noble gases ((3)He and (129)Xe) can provide NMR signal enhancements of 10,000 to 100,000 times that of thermally polarized gases and have shown great potential for applications in lung magnetic resonance imaging (MRI) by greatly enhancing the sensitivity and contrast. These gases obtain a highly polarized state by employing a spin exchange optical pumping technique. In this chapter, the underlying physics of spin exchange optical pumping for production of hyperpolarized noble gases is explained and the basic components and procedures for building a polarizer are described. The storage and delivery strategies of hyperpolarized gases for in vivo imaging are discussed. Many of the problems that are likely to be encountered in practical experiments and the corresponding detailed approaches to overcome them are also discussed.
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Affiliation(s)
- Xin Zhou
- Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, 430071 Wuhan, Hubei Province, China.
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8
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Ardenkjaer-Larsen JH, Jóhannesson H, Petersson JS, Wolber J. Applications of hyperpolarized agents in solutions. Methods Mol Biol 2011; 771:655-689. [PMID: 21874502 DOI: 10.1007/978-1-61779-219-9_33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This chapter provides an overview of pulse sequences adapted to hyperpolarized MR imaging. Applications of hyperpolarized agents in aqueous solution are reviewed. Vascular (e.g., angiography, perfusion, and catheter tracking) as well as metabolic (e.g., oncology, cardiology, neurology, and pH mapping) applications are covered. Due to the rapid development of new applications for hyperpolarized agents, a review format has been used for this chapter instead of a strict protocol/procedure structure.
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9
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Asfour A. A three-coil RF probe-head at 2.35 T: Potential applications to the (23)Na and to the hyperpolarized (129)Xe MRI in small animals. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2010:5693-9. [PMID: 21097320 DOI: 10.1109/iembs.2010.5627882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present in this paper a dedicated home-built RF probe-head for the MRI of rat brain at 2.35 T. This probe consists of an association of three coils: a double-tuned birdcage coil, which could be used for both transmitting and receiving, and a single-tuned surface coil that is used for the only receiving. This single-tuned coil is actively decoupled from the double-tuned volume coil. The active decoupling is based on the pole insertion technique using PIN diodes circuitry. This development was initially motivated by its potential and future application to the brain perfusion measurements by the MRI of hyperpolarized xenon-129 (HP (129)Xe). However, one of underlying ideas behind this work is to proceed well beyond this specific application. Particularly, the developed coil could also be dedicated for the sodium-23 ((23)Na) MRI in the rat brain. Indeed we tried to make the design versatile, simple and easy to replicate by other research groups, with a low cost, minimum development time and accepted performances. We believe that this design could by useful for groups who consider building own hardware. This is why we describe in some details the practical aspects of the workbench design as well as the coil characterization. For simplicity reasons, the first results of developed prototype were obtained at 100 MHz and 26.4 MHz (proton and sodium-23 frequencies at 2.35 T). MR images of phantoms were realized. In-vivo (1)H images and (23)Na spectra of the rat brain were also obtained. Future validation would concern the MRI of HP (129)Xe.
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Affiliation(s)
- Aktham Asfour
- INSERM, U836, GIN, Team 5, Grenoble, F-38000, France.
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10
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Zhou X, Graziani D, Pines A. Hyperpolarized xenon NMR and MRI signal amplification by gas extraction. Proc Natl Acad Sci U S A 2009; 106:16903-6. [PMID: 19805177 PMCID: PMC2749000 DOI: 10.1073/pnas.0909147106] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Indexed: 11/18/2022] Open
Abstract
A method is reported for enhancing the sensitivity of NMR of dissolved xenon by detecting the signal after extraction to the gas phase. We demonstrate hyperpolarized xenon signal amplification by gas extraction (Hyper-SAGE) in both NMR spectra and magnetic resonance images with time-of-flight information. Hyper-SAGE takes advantage of a change in physical phase to increase the density of polarized gas in the detection coil. At equilibrium, the concentration of gas-phase xenon is approximately 10 times higher than that of the dissolved-phase gas. After extraction the xenon density can be further increased by several orders of magnitude by compression and/or liquefaction. Additionally, being a remote detection technique, the Hyper-SAGE effect is further enhanced in situations where the sample of interest would occupy only a small proportion of the traditional NMR receiver. Coupled with targeted xenon biosensors, Hyper-SAGE offers another path to highly sensitive molecular imaging of specific cell markers by detection of exhaled xenon gas.
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Affiliation(s)
- Xin Zhou
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California, Berkeley, CA 94720
| | - Dominic Graziani
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California, Berkeley, CA 94720
| | - Alexander Pines
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Chemistry, University of California, Berkeley, CA 94720
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11
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Kimura A, Imai H, Wakayama T, Fujiwara H. A simple method for quantitative measurement and analysis of hyperpolarized (129)Xe uptake dynamics in mouse brain under controlled flow. Magn Reson Med Sci 2009; 7:179-85. [PMID: 19110512 DOI: 10.2463/mrms.7.179] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
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 flow 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 effect 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 flow 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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Affiliation(s)
- Atsuomi Kimura
- Division of Medical Physics and Engineering, Graduate School of Medicine, Osaka University. Osaka, Japan.
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12
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Zhou X, Mazzanti ML, Chen JJ, Tzeng YS, Mansour JK, Gereige JD, Venkatesh AK, Sun Y, Mulkern RV, Albert MS. Reinvestigating hyperpolarized (129)Xe longitudinal relaxation time in the rat brain with noise considerations. NMR IN BIOMEDICINE 2008; 21:217-25. [PMID: 17557274 DOI: 10.1002/nbm.1184] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The longitudinal relaxation time of hyperpolarized (HP) (129)Xe in the brain is a critical parameter for developing HP (129)Xe brain imaging and spectroscopy and optimizing the pulse sequences, especially in the case of cerebral blood flow measurements. Various studies have produced widely varying estimates of HP (129)Xe T(1) in the rat brain. To make improved measurements of HP (129)Xe T(1) in the rat brain and investigate how low signal-to-noise ratio (SNR) contributes to these discrepancies, we developed a multi-pulse protocol during the washout of (129)Xe from the brain. Afterwards, we applied an SNR threshold theory to both the multi-pulse protocol and an existing two-pulse protocol. The two protocols yielded mean +/- SD HP (129)Xe T(1) values in the rat brain of 15.3 +/- 1.2 and 16.2 +/- 0.9 s, suggesting that the low SNR might be a key reason for the wide range of T(1) values published in the literature, a problem that might be easily alleviated by taking SNR levels into account.
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Affiliation(s)
- X Zhou
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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13
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Kershaw J, Nakamura K, Kondoh Y, Wakai A, Suzuki N, Kanno I. Confirming the existence of five peaks in129Xe rat head spectra. Magn Reson Med 2007; 57:791-7. [PMID: 17390344 DOI: 10.1002/mrm.21186] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A series of experiments were performed to investigate why two peaks (D and E) of the five dissolved phase peaks in hyperpolarized (129)Xe rat head spectra appeared inconsistently in previous work. Specifically, spectra were acquired under conditions of various shim states, anaesthetics, and arterial ligation. The shimming experiments showed that slice-shimming can be used to improve resolution of the dissolved phase peaks, but even so, subtle changes in the shim state that may dramatically alter the shape of peak E remain poorly understood. Also, the inability to shim gas spaces and tissue simultaneously may explain why inconsistent chemical shift values have been reported in the literature. A possible solution for this problem is suggested. The results of pre- and postligation spectra from the same animal indicated that two peaks (A and E) originate from brain. Changing the anaesthetic was found to have no effect on the number of dissolved peaks in xenon spectra.
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Affiliation(s)
- Jeff Kershaw
- Akita Research Institute of Brain and Blood Vessels, Akita City, Japan.
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14
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Nakamura K, Kondoh Y, Wakai A, Kershaw J, Wright D, Kanno I. 129Xe spectra from the heads of rats with and without ligation of the external carotid and pterygopalatine arteries. Magn Reson Med 2005; 53:528-34. [PMID: 15723409 DOI: 10.1002/mrm.20399] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
After rats inhaled hyperpolarized (129)Xe gas, in vivo spectra from their heads revealed a dominant peak around 195 ppm, another easily resolvable peak near 189 ppm, a broad peak around 210 ppm, and two minor peaks around 198 ppm and 192 ppm. However, the source of each peak remains controversial. To further study the origin of each peak, we compared spectra obtained from the heads of normal rats with spectra taken from the heads of rats that had undergone ligation of the external carotid (ECA) and pterygopalatine (PPA) arteries, the major feeding vessels of nonbrain tissue in the rat head. The amplitude of the peak at around 189 ppm was greatly reduced in the ECA/PPA-ligated rats, while the peak around 195 ppm persisted. We conclude that the signal that originates from the rat brain after inhalation of (129)Xe gas is overwhelmingly dominated by the single resonance at 195 ppm.
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Affiliation(s)
- Kazuhiro Nakamura
- Akita Research Institute of Brain and Blood Vessels, Noken Center, 6-10 Senshu-Kubota Machi, Akita 010-0874, Japan.
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15
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Wakai A, Nakamura K, Kershaw J, Kanno I. In vivo MR spectroscopy of hyperpolarized Xe-129 in rat brain. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.ics.2004.04.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Sato H, Enmi JI, Hayashi T, Takei N, Iwadate Y, Abe S, Teramoto N, Kawachi N, Hattori M, Watabe H, Sawada T, Uchiyama K, Tsukamoto T, Nagasawa K, Iida H. Development of a hyperpolarized 129Xe system on 3T for the rat lungs. Magn Reson Med Sci 2004; 3:1-9. [PMID: 16093614 DOI: 10.2463/mrms.3.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
MRI (magnetic resonance imaging) with 129Xe has gained much attention as a diagnostic methodology because of its affinity for lipids and possible polarization. The quantitative estimation of net detectability and stability of hyperpolarized 129Xe 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 129Xe experimental 3T system to statistically analyze the dissolved-phase 129Xe signal in the rat lungs. The polarization of 129Xe with buffer 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 insufflated 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 129Xe signal in the dissolved phase to measure the chemical shift, T2*, delay and its ratio in a rat lungs on 3T. The polarizer was able to produce polarized gas (1.1+/-0.47%, 120 cm3) hundreds of times with the laser absorption ratio (25%) kept constant at the cell. The optimal buffer gas ratio of 25-50% 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+/-5.2% and 4.4+/-4.7%, respectively. The T2* 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 129Xe experimental system using a 3T MRI scanner that yields sufficient volume and polarization and quantitatively analyzed the dissolved-phase 129Xe signal in the rat lungs.
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Affiliation(s)
- Hiroshi Sato
- Department of Investigative Radiology, Research Institute of National Cardiovascular Center, Suita. Osaka, Japan.
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17
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Affiliation(s)
- Robert F Mattrey
- Dept of Radiology, University of California, San Diego, 410 Dickinson St., San Diego, CA 92103, USA
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18
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Choquet P, Hyacinthe JN, Duhamel G, Grillon E, Leviel JL, Constantinesco A, Ziegler A. Method to determine in vivo the relaxation time T1 of hyperpolarized xenon in rat brain. Magn Reson Med 2003; 49:1014-8. [PMID: 12768578 DOI: 10.1002/mrm.10471] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The magnetic polarization of the stable (129)Xe isotope may be enhanced dramatically by means of optical techniques and, in principle, hyperpolarized (129)Xe MRI should allow quantitative mapping of cerebral blood flow with better spatial resolution than scintigraphic techniques. A parameter necessary for this quantitation, and not previously known, is the longitudinal relaxation time (T(1) (tissue)) of (129)Xe in brain tissue in vivo: a method for determining this is reported. The time course of the MR signal in the brain during arterial injection of hyperpolarized (129)Xe in a lipid emulsion was analyzed using an extended two-compartment model. The model uses experimentally determined values of the RF flip angle and the T(1) of (129)Xe in the lipid emulsion. Measurements on rats, in vivo, at 2.35 T gave T(1) (tissue) = 3.6 +/- 2.1 sec (+/-SD, n = 6). This method enables quantitative mapping of cerebral blood flow.
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Affiliation(s)
- Philippe Choquet
- Laboratoire de Biomécanique, Université Louis Pasteur, Centre Hospitalier Universitaire Hautepierre, Strasbourg, France
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