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Lee SJ, Park I, Talbott JF, Gordon J. Investigating the Feasibility of In Vivo Perfusion Imaging Methods for Spinal Cord Using Hyperpolarized [ 13C]t-Butanol and [ 13C, 15N 2]Urea. Mol Imaging Biol 2021; 24:371-376. [PMID: 34779970 DOI: 10.1007/s11307-021-01682-1] [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: 06/21/2021] [Revised: 09/30/2021] [Accepted: 11/02/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE This study examined the feasibility of using two novel agents, hyperpolarized [13C]t-butanol and [13C,15N2]urea, for assessing in vivo perfusion of the intact spinal cord in rodents. Due to their distinct permeabilities to blood brain barrier (BBB), we hypothesized that [13C]t-butanol and [13C,15N2]urea exhibit unique 13C signal characteristics in the spinal cord. PROCEDURES Dynamic 13C t-butanol MRI data were acquired from healthy Long-Evans rats using a symmetric, ramp-sampled, partial-Fourier 13C echo-planar imaging sequence after the injection of hyperpolarized [13C]t-butanol solution. In subsequent scans, dynamic 13C urea MRI data were acquired after the injection of hyperpolarized [13C,15N2]urea. The SNRs of t-butanol and urea were calculated for regions corresponding to spine, supratentorial brain, and blood vessels and plotted over time. Mean peak SNR and AUC were calculated from the dynamic plots for each region and compared between t-butanol and urea. RESULTS In spine and supratentorial brain, the mean peak SNR and AUC of t-butanol were significantly higher than those of urea (p < 0.05). In contrast, urea was predominantly contained within vasculature and exhibited significantly higher levels of mean peak SNR and AUC compared to t-butanol in blood vessels (p < 0.05). CONCLUSION This study has demonstrated the feasibility of using hyperpolarized [13C]t-butanol and [13C,15N2]urea for assessing in vivo perfusion in cervical spinal cord. Due to differences in blood-brain barrier permeability, t-butanol rapidly crossed the blood-brain barrier and diffused into spine and brain tissue, while urea predominantly remained in vasculature. The results from this study suggest that this technique may provide unique non-invasive imaging tracers that are able to directly monitor hemodynamic processes in the normal and injured spinal cord.
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Affiliation(s)
- Seung Jin Lee
- Department of Radiology, Chonnam National University Hospital, 42 Jaebongro, Donggu, Gwangju, 61469, South Korea
| | - Ilwoo Park
- Department of Radiology, Chonnam National University Hospital, 42 Jaebongro, Donggu, Gwangju, 61469, South Korea. .,Department of Radiology, Chonnam National University, 42 Jaebongro, Donggu, Gwangju, 61469, South Korea. .,Department of Artificial Intelligence Convergence, Chonnam National University, 77 Yongbongro, Bukgu, Gwangju, 61186, South Korea.
| | - Jason F Talbott
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, 94143, USA.,Brain and Spine Injury Center (BASIC), San Francisco General Hospital, University of California, San Francisco, CA, 94110, USA
| | - Jeremy Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, 94143, USA
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Michel KA, Ragavan M, Walker CM, Merritt ME, Lai SY, Bankson JA. Comparison of selective excitation and multi-echo chemical shift encoding for imaging of hyperpolarized [1- 13C]pyruvate. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 325:106927. [PMID: 33607386 PMCID: PMC8009829 DOI: 10.1016/j.jmr.2021.106927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 12/31/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Imaging methods for hyperpolarized (HP) 13C agents must sample the evolution of signal from multiple agents with distinct chemical shifts within a very brief timeframe (typically < 1 min), which is challenging using conventional imaging methods. In this work, we compare two of the most commonly used HP spectroscopic imaging methods, spectral-spatial selective excitation and multi-echo chemical shift encoding (CSE, also referred to as IDEAL), for a typical preclinical HP [1-13C]pyruvate imaging scan at 7 T. Both spectroscopic encoding techniques were implemented and validated in HP experiments imaging enzyme phantoms and the murine kidney. SNR performance of these two spectroscopic imaging approaches was compared in numerical simulations and phantom experiments using a single-shot flyback EPI readout for spatial encoding. With identical effective excitation angles, the SNR of images acquired with spectral-spatial excitations and CSE were found to be effectively equivalent.
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Affiliation(s)
- Keith A Michel
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; Medical Physics Graduate Program, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Mukundan Ragavan
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States
| | - Christopher M Walker
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, United States
| | - Stephen Y Lai
- Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - James A Bankson
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; Medical Physics Graduate Program, The University of Texas MD Anderson Cancer Center, UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States.
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Topping GJ, Heid I, Trajkovic-Arsic M, Kritzner L, Grashei M, Hundshammer C, Aigner M, Skinner JG, Braren R, Schilling F. Hyperpolarized 13C Spectroscopy with Simple Slice-and-Frequency-Selective Excitation. Biomedicines 2021; 9:biomedicines9020121. [PMID: 33513763 PMCID: PMC7911979 DOI: 10.3390/biomedicines9020121] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/16/2021] [Accepted: 01/23/2021] [Indexed: 01/01/2023] Open
Abstract
Hyperpolarized 13C nuclear magnetic resonance spectroscopy can characterize in vivo tissue metabolism, including preclinical models of cancer and inflammatory disease. Broad bandwidth radiofrequency excitation is often paired with free induction decay readout for spectral separation, but quantification of low-signal downstream metabolites using this method can be impeded by spectral peak overlap or when frequency separation of the detected peaks exceeds the excitation bandwidth. In this work, alternating frequency narrow bandwidth (250 Hz) slice-selective excitation was used for 13C spectroscopy at 7 T in a subcutaneous xenograft rat model of human pancreatic cancer (PSN1) to improve quantification while measuring the dynamics of injected hyperpolarized [1-13C]lactate and its metabolite [1-13C]pyruvate. This method does not require sophisticated pulse sequences or specialized radiofrequency and gradient pulses, but rather uses nominally spatially offset slices to produce alternating frequency excitation with simpler slice-selective radiofrequency pulses. Additionally, point-resolved spectroscopy was used to calibrate the 13C frequency from the thermal proton signal in the target region. This excitation scheme isolates the small [1-13C]pyruvate peak from the similar-magnitude tail of the much larger injected [1-13C]lactate peak, facilitates quantification of the [1-13C]pyruvate signal, simplifies data processing, and could be employed for other substrates and preclinical models.
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Affiliation(s)
- Geoffrey J. Topping
- Department of Nuclear Medicine, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (G.J.T.); (M.G.); (C.H.); (M.A.); (J.G.S.)
| | - Irina Heid
- Institute of Diagnostic and Interventional Radiology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (I.H.); (L.K.); (R.B.)
| | - Marija Trajkovic-Arsic
- Division of Solid Tumor Translational Oncology, German Cancer Consortium (DKTK, Partner Site Essen), 45147 Essen, Germany;
- German Cancer Research Center, DKFZ, 69120 Heidelberg, Germany
- Institute of Developmental Cancer Therapeutics, West German Cancer Center, University Hospital Essen, 45147 Essen, Germany
| | - Lukas Kritzner
- Institute of Diagnostic and Interventional Radiology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (I.H.); (L.K.); (R.B.)
| | - Martin Grashei
- Department of Nuclear Medicine, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (G.J.T.); (M.G.); (C.H.); (M.A.); (J.G.S.)
| | - Christian Hundshammer
- Department of Nuclear Medicine, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (G.J.T.); (M.G.); (C.H.); (M.A.); (J.G.S.)
| | - Maximilian Aigner
- Department of Nuclear Medicine, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (G.J.T.); (M.G.); (C.H.); (M.A.); (J.G.S.)
| | - Jason G. Skinner
- Department of Nuclear Medicine, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (G.J.T.); (M.G.); (C.H.); (M.A.); (J.G.S.)
| | - Rickmer Braren
- Institute of Diagnostic and Interventional Radiology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (I.H.); (L.K.); (R.B.)
- German Cancer Consortium (DKTK, Partner Site Munich), 81675 Munich, Germany
| | - Franz Schilling
- Department of Nuclear Medicine, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (G.J.T.); (M.G.); (C.H.); (M.A.); (J.G.S.)
- Correspondence:
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Timm KN, Miller JJ, Henry JA, Tyler DJ. Cardiac applications of hyperpolarised magnetic resonance. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 106-107:66-87. [PMID: 31047602 DOI: 10.1016/j.pnmrs.2018.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/14/2018] [Accepted: 05/29/2018] [Indexed: 05/05/2023]
Abstract
Cardiovascular disease is the leading cause of death world-wide. It is increasingly recognised that cardiac pathologies show, or may even be caused by, changes in metabolism, leading to impaired cardiac energetics. The heart turns over 15 times its own weight in ATP every day and thus relies heavily on the availability of substrates and on efficient oxidation to generate this ATP. A number of old and emerging drugs that target different aspects of metabolism are showing promising results with regard to improved cardiac outcomes in patients. A non-invasive imaging technique that could assess the role of different aspects of metabolism in heart disease, as well as measure changes in cardiac energetics due to treatment, would be valuable in the routine clinical care of cardiac patients. Hyperpolarised magnetic resonance spectroscopy and imaging have revolutionised metabolic imaging, allowing real-time metabolic flux assessment in vivo for the first time. In this review we summarise metabolism in the healthy and diseased heart, give an introduction to the hyperpolarisation technique, 'dynamic nuclear polarisation' (DNP), and review the preclinical studies that have thus far explored healthy cardiac metabolism and different models of human heart disease. We furthermore show what advances have been made to translate this technique into the clinic, what technical challenges still remain and what unmet clinical needs and unexplored metabolic substrates still need to be assessed by researchers in this exciting and fast-moving field.
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Affiliation(s)
- Kerstin N Timm
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK.
| | - Jack J Miller
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK; Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Oxford, UK; Clarendon Laboratory, Department of Physics, University of Oxford, UK.
| | - John A Henry
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK.
| | - Damian J Tyler
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK; Oxford Centre for Clinical Magnetic Resonance Research, John Radcliffe Hospital, Oxford, UK.
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Lee H, Song JE, Shin J, Joe E, Joo CG, Choi YS, Song HT, Kim DH. High resolution hyperpolarized 13 C MRSI using SPICE at 9.4T. Magn Reson Med 2018; 80:703-710. [PMID: 29315780 DOI: 10.1002/mrm.27061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/13/2017] [Accepted: 12/05/2017] [Indexed: 12/13/2022]
Abstract
PURPOSE To test the feasibility of using the SPICE (SPectroscopic Imaging by exploiting spatiospectral CorrElation) technique, which uses the partial separability of spectroscopic data, for high resolution hyperpolarized (HP) 13 C spectroscopic imaging. METHODS Numerical simulations were performed to investigate the impact of transient HP signals on SPICE reconstruction. Furthermore, spectroscopic imaging exams from SPICE and conventional EPSI (echo-planar spectroscopic imaging) were simulated for comparison. For in vivo experiments, HP 13 C SPICE was performed in a mouse kidney by means of the injection of HP [1-13 C] pyruvate at 9.4T. RESULTS The variation of lactate/pyruvate from the simulated SPICE was less than 4% under various factors that affect the transient HP signal, suggesting that the impact is negligible. We found that while HP 13 C EPSI was limited to the low signal-to-noise ratio (SNR) of lactate, these limitations were mitigated through HP 13 C SPICE, facilitating the improved SNR of lactate and the distinction of tissues. Acquisition of a high resolution HP 13 C spectroscopic image was possible for the in vivo experiments. With the fine structural information, the acquired image showed higher signal of pyruvate and lactate in the renal cortices than in the medullas, which is known to be attributed to higher activity of lactate dehydrogenase. CONCLUSION The feasibility of HP 13 C SPICE was investigated. Simulation studies were conducted and in vivo experiments were performed in the mouse kidney at 9.4T. Results confirmed that a high resolution HP 13 C spectroscopic image with adequate spectral resolution can be obtained. Magn Reson Med 80:703-710, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hansol Lee
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Jae Eun Song
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Jaewook Shin
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Eunhae Joe
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Chan Gyu Joo
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Young-Suk Choi
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Ho-Taek Song
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Dong-Hyun Kim
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
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Joe E, Lee H, Lee J, Yang S, Choi YS, Wang E, Song HT, Kim DH. An indirect method for in vivo T 2 mapping of [1- 13 C] pyruvate using hyperpolarized 13 C CSI. NMR IN BIOMEDICINE 2017; 30:e3690. [PMID: 28111820 DOI: 10.1002/nbm.3690] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 06/06/2023]
Abstract
An indirect method for in vivo T2 mapping of 13 C-labeled metabolites using T2 and T2 * information of water protons obtained a priori is proposed. The T2 values of 13 C metabolites are inferred using the relationship to T2 ' of coexisting 1 H and the T2 * of 13 C metabolites, which is measured using routine hyperpolarized 13 C CSI data. The concept is verified with phantom studies. Simulations were performed to evaluate the extent of T2 estimation accuracy due to errors in the other measurements. Also, bias in the 13 C T2 * estimation from the 13 C CSI data was studied. In vivo experiments were performed from the brains of normal rats and a rat with C6 glioma. Simulation results indicate that the proposed method provides accurate and unbiased 13 C T2 values within typical experimental settings. The in vivo studies found that the estimated T2 of [1-13 C] pyruvate using the indirect method was longer in tumor than in normal tissues and gave values similar to previous reports. This method can estimate localized T2 relaxation times from multiple voxels using conventional hyperpolarized 13 C CSI and can potentially be used with time resolved fast CSI.
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Affiliation(s)
- Eunhae Joe
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Hansol Lee
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Joonsung Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University, Suwon, Korea
| | - Seungwook Yang
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Young-Suk Choi
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Eunkyung Wang
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Ho-Taek Song
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Dong-Hyun Kim
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
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Siddiqui S, Kadlecek S, Pourfathi M, Xin Y, Mannherz W, Hamedani H, Drachman N, Ruppert K, Clapp J, Rizi R. The use of hyperpolarized carbon-13 magnetic resonance for molecular imaging. Adv Drug Deliv Rev 2017; 113:3-23. [PMID: 27599979 PMCID: PMC5783573 DOI: 10.1016/j.addr.2016.08.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/25/2016] [Accepted: 08/27/2016] [Indexed: 02/06/2023]
Abstract
Until recently, molecular imaging using magnetic resonance (MR) has been limited by the modality's low sensitivity, especially with non-proton nuclei. The advent of hyperpolarized (HP) MR overcomes this limitation by substantially enhancing the signal of certain biologically important probes through a process known as external nuclear polarization, enabling real-time assessment of tissue function and metabolism. The metabolic information obtained by HP MR imaging holds significant promise in the clinic, where it could play a critical role in disease diagnosis and therapeutic monitoring. This review will provide a comprehensive overview of the developments made in the field of hyperpolarized MR, including advancements in polarization techniques and delivery, probe development, pulse sequence optimization, characterization of healthy and diseased tissues, and the steps made towards clinical translation.
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Affiliation(s)
- Sarmad Siddiqui
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mehrdad Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yi Xin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William Mannherz
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hooman Hamedani
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicholas Drachman
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kai Ruppert
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Justin Clapp
- Department of Anesthesiology and Critical Care, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rahim Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Guduff L, Allami AJ, van Heijenoort C, Dumez JN, Kuprov I. Efficient simulation of ultrafast magnetic resonance experiments. Phys Chem Chem Phys 2017; 19:17577-17586. [DOI: 10.1039/c7cp03074f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We present a convenient and powerful simulation formalism for ultrafast NMR spectroscopy. The formalism is based on the Fokker–Planck equation that supports systems with complicated combinations of classical spatial dynamics and quantum mechanical spin dynamics.
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Affiliation(s)
- Ludmilla Guduff
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Université Paris Sud
- Université Paris-Saclay
- 91190 Gif-sur-Yvette
| | | | - Carine van Heijenoort
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Université Paris Sud
- Université Paris-Saclay
- 91190 Gif-sur-Yvette
| | - Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Université Paris Sud
- Université Paris-Saclay
- 91190 Gif-sur-Yvette
| | - Ilya Kuprov
- School of Chemistry
- University of Southampton
- Southampton
- UK
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Lee H, Lee J, Joe E, Yang S, Song JE, Choi YS, Wang E, Joo CG, Song HT, Kim DH. Flow-suppressed hyperpolarized 13 C chemical shift imaging using velocity-optimized bipolar gradient in mouse liver tumors at 9.4 T. Magn Reson Med 2016; 78:1674-1682. [PMID: 28019020 DOI: 10.1002/mrm.26578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 12/21/2022]
Abstract
PURPOSE To optimize and investigate the influence of bipolar gradients for flow suppression in metabolic quantification of hyperpolarized 13 C chemical shift imaging (CSI) of mouse liver at 9.4 T. METHODS The trade-off between the amount of flow suppression using bipolar gradients and T2* effect from static spins was simulated. A free induction decay CSI sequence with alternations between the flow-suppressed and non-flow-suppressed acquisitions for each repetition time was developed and was applied to liver tumor-bearing mice via injection of hyperpolarized [1-13 C] pyruvate. RESULTS The in vivo results from flow suppression using the velocity-optimized bipolar gradient were comparable with the simulation results. The vascular signal was adequately suppressed and signal loss in stationary tissue was minimized. Application of the velocity-optimized bipolar gradient to tumor-bearing mice showed reduction in the vessel-derived pyruvate signal contamination, and the average lactate/pyruvate ratio increased by 0.095 (P < 0.05) in the tumor region after flow suppression. CONCLUSION Optimization of the bipolar gradient is essential because of the short 13 C T2* and high signal in venous flow in the mouse liver. The proposed velocity-optimized bipolar gradient can suppress the vascular signal, minimizing T2*-related signal loss in stationary tissues at 9.4 T. Magn Reson Med 78:1674-1682, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hansol Lee
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Joonsung Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea
| | - Eunhae Joe
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Seungwook Yang
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Jae Eun Song
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Young-Suk Choi
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Eunkyung Wang
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Chan Gyu Joo
- Severance Biomedical Science Institute, College of Medicine, Yonsei University, Seoul, Korea
| | - Ho-Taek Song
- Department of Radiology, College of Medicine, Yonsei University, Seoul, Korea
| | - Dong-Hyun Kim
- Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
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