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Oba M, Taguchi M, Kudo Y, Yamashita K, Yasui H, Matsumoto S, Kirilyuk IA, Inanami O, Hirata H. Partial Acquisition of Spectral Projections Accelerates Four-dimensional Spectral-spatial EPR Imaging for Mouse Tumor Models: A Feasibility Study. Mol Imaging Biol 2024; 26:459-472. [PMID: 38811467 DOI: 10.1007/s11307-024-01924-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/16/2024] [Accepted: 05/20/2024] [Indexed: 05/31/2024]
Abstract
PURPOSE Our study aimed to accelerate the acquisition of four-dimensional (4D) spectral-spatial electron paramagnetic resonance (EPR) imaging for mouse tumor models. This advancement in EPR imaging should reduce the acquisition time of spectroscopic mapping while reducing quality degradation for mouse tumor models. PROCEDURES EPR spectra under magnetic field gradients, called spectral projections, were partially measured. Additional spectral projections were later computationally synthesized from the measured spectral projections. Four-dimensional spectral-spatial images were reconstructed from the post-processed spectral projections using the algebraic reconstruction technique (ART) and assessed in terms of their image qualities. We applied this approach to a sample solution and a mouse Hs766T xenograft model of human-derived pancreatic ductal adenocarcinoma cells to demonstrate the feasibility of our concept. The nitroxyl radical imaging agent 2H,15N-DCP was exogenously infused into the mouse xenograft model. RESULTS The computation code of 4D spectral-spatial imaging was tested with numerically generated spectral projections. In the linewidth mapping of the sample solution, we achieved a relative standard uncertainty (standard deviation/| mean |) of 0.76 μT/45.38 μT = 0.017 on the peak-to-peak first-derivative EPR linewidth. The qualities of the linewidth maps and the effect of computational synthesis of spectral projections were examined. Finally, we obtained the three-dimensional linewidth map of 2H,15N-DCP in a Hs766T tumor-bearing leg in vivo. CONCLUSION We achieved a 46.7% reduction in the acquisition time of 4D spectral-spatial EPR imaging without significantly degrading the image quality. A combination of ART and partial acquisition in three-dimensional raster magnetic field gradient settings in orthogonal coordinates is a novel approach. Our approach to 4D spectral-spatial EPR imaging can be applied to any subject, especially for samples with less variation in one direction.
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Affiliation(s)
- Misa Oba
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Mai Taguchi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Yohei Kudo
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Koya Yamashita
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo, 060-0818, Japan
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo, 060-0818, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Igor A Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, 9, Ac. Lavrentieva Ave, Novosibirsk, 630090, Russia
| | - Osamu Inanami
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo, 060-0818, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan.
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Sato-Akaba H, Sakai T, Hirata H. Generation of transmission wave with low AM noise for sub-GHz CW-EPR spectrometer. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2024; 360:107633. [PMID: 38394999 DOI: 10.1016/j.jmr.2024.107633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/13/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024]
Abstract
This study describes a technique to clean amplitude modulation (AM) noise of RF transmission waves, which is used to observe the sub-GHz CW-EPR spectrum. An RF transmitter amplifier that has the function of cleaning AM noise has been developed. Cleaning of the AM noise was owing to saturation of the output at the amplifier. Three stages of the amplifiers in series could effectively suppress the AM noise to about -176 dBc/Hz and -183 dBc/Hz at offset frequency of 10 kHz and 100 kHz, respectively at the carrier frequency of 750 MHz and the output power of 29 dBm. Since phase modulation (PM) noise is suppressed by phase sensitive detection, the AM noise in the transmission is dominant cause of the noise in the sub-GHz CW-EPR absorption spectrum using a reflection bridge, which depends on the quality factor of the resonator and the power of the RF transmission. The additive phase modulation (PM) noise of this amplifier was -171 dBc/Hz at an offset frequency of 100 kHz, which indicated that the frequency modulation (FM) of the transmission wave was not distorted with this amplifier. Therefore, conventional CW-EPR spectrometers that typically require FM for automatic frequency control or automatic tunning control can use this technique to increase sensitivity.
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Affiliation(s)
- Hideo Sato-Akaba
- Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan.
| | - Tsukasa Sakai
- Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
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Nakaoka R, Kato K, Yamamoto K, Yasui H, Matsumoto S, Kirilyuk IA, Khramtsov VV, Inanami O, Hirata H. Electron Paramagnetic Resonance Implemented with Multiple Harmonic Detections Successfully Maps Extracellular pH In Vivo. Anal Chem 2023; 95:3940-3950. [PMID: 36725678 PMCID: PMC9979135 DOI: 10.1021/acs.analchem.2c03194] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Extracellular acidification indicates a metabolic shift in cancer cells and is, along with tissue hypoxia, a hallmark of tumor malignancy. Thus, non-invasive mapping of extracellular pH (pHe) is essential for researchers to understand the tumor microenvironment and to monitor tumor response to metabolism-targeting drugs. While electron paramagnetic resonance (EPR) has been successfully used to map pHe in mouse xenograft models, this method is not sensitive enough to map pHe with a moderate amount of exogenous pH-sensitive probes. Here, we show that a modified EPR system achieves twofold higher sensitivity by using the multiple harmonic detection (MHD) method and improves the robustness of pHe mapping in mouse xenograft models. Our results demonstrate that treatment of a mouse xenograft model of human-derived pancreatic ductal adenocarcinoma cells with the carbonic anhydrase IX (CAIX) inhibitor U-104 delays tumor growth with a concurrent tendency toward further extracellular acidification. We anticipate that EPR-based pHe mapping can be expanded to monitor the response of other metabolism-targeting drugs. Furthermore, pHe monitoring can also be used for the development of improved metabolism-targeting cancer treatments.
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Affiliation(s)
- Ririko Nakaoka
- Division
of Bioengineering and Bioinformatics, Graduate School of Information
Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo060-0814, Japan
| | - Kazuhiro Kato
- Laboratory
of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo060-0818, Japan
| | - Kumiko Yamamoto
- Laboratory
of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo060-0818, Japan
| | - Hironobu Yasui
- Laboratory
of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo060-0818, Japan
| | - Shingo Matsumoto
- Division
of Bioengineering and Bioinformatics, Faculty of Information Science
and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo060-0814, Japan
| | - Igor A. Kirilyuk
- N.N.
Vorozhtsov Novosibirsk Institute of Organic Chemistry, 9, Ac. Lavrentieva Ave., Novosibirsk630090, Russia
| | - Valery V. Khramtsov
- Department
of Biochemistry and Molecular Medicine, and In Vivo Multifunctional
Magnetic Resonance Center, West Virginia
University Robert C. Byrd Health Sciences Center, 1 Medical Center Drive, Morgantown, West Virginia26506, United States
| | - Osamu Inanami
- Laboratory
of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo060-0818, Japan
| | - Hiroshi Hirata
- Division
of Bioengineering and Bioinformatics, Faculty of Information Science
and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo060-0814, Japan,
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Takakusagi Y, Kobayashi R, Saito K, Kishimoto S, Krishna MC, Murugesan R, Matsumoto KI. EPR and Related Magnetic Resonance Imaging Techniques in Cancer Research. Metabolites 2023; 13:metabo13010069. [PMID: 36676994 PMCID: PMC9862119 DOI: 10.3390/metabo13010069] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023] Open
Abstract
Imaging tumor microenvironments such as hypoxia, oxygenation, redox status, and/or glycolytic metabolism in tissues/cells is useful for diagnostic and prognostic purposes. New imaging modalities are under development for imaging various aspects of tumor microenvironments. Electron Paramagnetic Resonance Imaging (EPRI) though similar to NMR/MRI is unique in its ability to provide quantitative images of pO2 in vivo. The short electron spin relaxation times have been posing formidable challenge to the technology development for clinical application. With the availability of the narrow line width trityl compounds, pulsed EPR imaging techniques were developed for pO2 imaging. EPRI visualizes the exogenously administered spin probes/contrast agents and hence lacks the complementary morphological information. Dynamic nuclear polarization (DNP), a phenomenon that transfers the high electron spin polarization to the surrounding nuclear spins (1H and 13C) opened new capabilities in molecular imaging. DNP of 13C nuclei is utilized in metabolic imaging of 13C-labeled compounds by imaging specific enzyme kinetics. In this article, imaging strategies mapping physiologic and metabolic aspects in vivo are reviewed within the framework of their application in cancer research, highlighting the potential and challenges of each of them.
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Affiliation(s)
- Yoichi Takakusagi
- Quantum Hyperpolarized MRI Research Team, Institute for Quantum Life Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
- Department of Quantum Life Science, Graduate School of Science, Chiba University, Chiba 265-8522, Japan
- Correspondence: (Y.T.); (K.-i.M.); Tel.: +81-43-382-4297 (Y.T.); +81-43-206-3123 (K.-i.M.)
| | - Ryoma Kobayashi
- Quantum Hyperpolarized MRI Research Team, Institute for Quantum Life Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
| | - Keita Saito
- Quantum Hyperpolarized MRI Research Team, Institute for Quantum Life Science, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
| | - Shun Kishimoto
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA
| | - Murali C. Krishna
- Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1002, USA
| | - Ramachandran Murugesan
- Karpaga Vinayaga Institute of Medical Sciences and Research Center, Palayanoor (PO), Chengalpattu 603308, India
| | - Ken-ichiro Matsumoto
- Quantitative RedOx Sensing Group, Department of Radiation Regulatory Science Research, National Institute of Radiological Sciences, Quantum Life and Medical Science Directorate, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-Ku, Chiba 263-8555, Japan
- Correspondence: (Y.T.); (K.-i.M.); Tel.: +81-43-382-4297 (Y.T.); +81-43-206-3123 (K.-i.M.)
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Kimura K, Iguchi N, Nakano H, Yasui H, Matsumoto S, Inanami O, Hirata H. Redox-Sensitive Mapping of a Mouse Tumor Model Using Sparse Projection Sampling of Electron Paramagnetic Resonance. Antioxid Redox Signal 2022; 36:57-69. [PMID: 33847172 PMCID: PMC8823265 DOI: 10.1089/ars.2021.0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Aims: This work aimed to establish an accelerated imaging system for redox-sensitive mapping in a mouse tumor model using electron paramagnetic resonance (EPR) and nitroxyl radicals. Results: Sparse sampling of EPR spectral projections was demonstrated for a solution phantom. The reconstructed three-dimensional (3D) images with filtered back-projection (FBP) and compressed sensing image reconstruction were quantitatively assessed for the solution phantom. Mouse xenograft models of a human-derived pancreatic ductal adenocarcinoma cell line, MIA PaCa-2, were also measured for redox-sensitive mapping with the sparse sampling technique. Innovation: A short-lifetime redox-sensitive nitroxyl radical (15N-labeled perdeuterated Tempone) could be measured to map the decay rates of the EPR signals for the mouse xenograft models. Acceleration of 3D EPR image acquisition broadened the choices of nitroxyl radical probes with various redox sensitivities to biological environments. Conclusion: Sparse sampling of EPR spectral projections accelerated image acquisition in the 3D redox-sensitive mapping of mouse tumor-bearing legs fourfold compared with conventional image acquisition with FBP. Antioxid. Redox Signal. 36, 57-69.
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Affiliation(s)
- Kota Kimura
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Nami Iguchi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Hitomi Nakano
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, Sapporo, Japan
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6
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Samouilov A, Komarov D, Petryakov S, Iosilevich A, Zweier JL. Development of an L-band resonator optimized for fast scan EPR imaging of the mouse head. Magn Reson Med 2021; 86:2316-2327. [PMID: 33938574 PMCID: PMC8295191 DOI: 10.1002/mrm.28821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE To develop a novel resonator for high-quality fast scan electron paramagnetic resonance (EPR) and EPR/NMR co-imaging of the head and brain of mice at 1.25 GHz. METHODS Resonator dimensions were scaled to fit the mouse head with maximum filling factor. A single-loop 6-gap resonator of 20 mm diameter and 20 mm length was constructed. High resonator stability was achieved utilizing a fixed position double coupling loop. Symmetrical mutually inverted connections rendered it insensitive to field modulation and fast scan. Coupling adjustment was provided by a parallel-connected variable capacitor located at the feeding line at λ/4 distance. To minimize radiation loss, the shield around the resonator was supplemented with a planar conductive disc that focuses return magnetic flux. RESULTS Coupling of the resonator loaded with the mouse head was efficient and easy. This resonator enabled high-quality in vivo 3D EPR imaging of the mouse head following intravenous infusion of nitroxide probes. With this resonator and rapid scan EPR system, 4 ms scans were acquired in forward and reverse directions so that images with 2-scan 3,136 projections were acquired in 25 s. Head images were achieved with resolutions of 0.4 mm, enabling visualization of probe localization and uptake across the blood-brain barrier. CONCLUSIONS This resonator design provides good sensitivity, high stability, and B1 field homogeneity for in vivo fast scan EPR of the mouse head and brain, enabling faster measurements and higher resolution imaging of probe uptake, localization, and metabolism than previously possible.
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Affiliation(s)
- Alexandre Samouilov
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Denis Komarov
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Sergey Petryakov
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Arkadiy Iosilevich
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
| | - Jay L. Zweier
- Davis Heart and Lung Research Institute, and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210 USA
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7
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Komarov DA, Samouilov A, Hirata H, Zweier JL. High fidelity triangular sweep of the magnetic field for millisecond scan EPR imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 329:107024. [PMID: 34198184 PMCID: PMC8316393 DOI: 10.1016/j.jmr.2021.107024] [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: 04/22/2021] [Revised: 05/28/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
Linearity of the magnetic field sweep is important for high resolution continuous wave EPR imaging. Driving the field with triangular wave function is the most efficient way to scan EPR projections. However, the magnetic field sweep profile can be significantly distorted during fast millisecond projection scan. In this work, we introduce a method to generate highly linear and properly symmetrical triangular sweeps of the magnetic field using calibrated harmonics of the triangular wave function. First, the frequency response function of the EPR magnet and its power circuitry was obtained. For this, the field sweeping coil was driven with sinusoidal signals of different frequencies and the actual magnetic field inside the magnet was recorded. To cover wide range of frequencies, the measurements were carried out independently using gaussmeter, Hall-effect linear sensor integrated circuit, and an inductance coil. For each frequency, the system gain and the phase delay were determined. These data were used to adjust the amplitudes and the phases of individual harmonics of the triangular wave function. After the calibration, the maximum deviation of the magnetic field from the linear function was 0.05% of sweep width for 4 ms scan. The maximum discrepancy between the forward and the reverse scan was less than 0.04%. Sweep overhead time for changing the scan direction was 5%. The proposed approach allows generation of high fidelity triangular magnetic field sweeps with accuracy better than 0.1% for the range of the magnetic field sweep widths up to 48 G and scan duration from 10 s down to 1 ms.
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Affiliation(s)
- Denis A Komarov
- The EPR Center and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Alexandre Samouilov
- The EPR Center and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Faculty of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Jay L Zweier
- The EPR Center and Department of Internal Medicine, Division of Cardiovascular Medicine, Davis Heart and Lung Institute, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
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Taguchi A, DeVience S, Driesschaert B, Khramtsov VV, Hirata H. In vitro simultaneous mapping of the partial pressure of oxygen, pH and inorganic phosphate using electron paramagnetic resonance. Analyst 2020; 145:3236-3244. [PMID: 32134072 DOI: 10.1039/d0an00168f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The partial pressure of oxygen (pO2) and the extracellular pH in the tumour microenvironment are essential parameters for understanding the physiological state of a solid tumour. Also, phosphate-containing metabolites are involved in energy metabolism, and interstitial inorganic phosphate (Pi) is an informative marker for tumour growth. This article describes the simultaneous mapping of pO2, pH and Pi using 750 MHz continuous-wave (CW) electron paramagnetic resonance (EPR) and a multifunctional probe, monophosphonated trityl radical p1TAM-D. The concept was demonstrated by acquiring three-dimensional (3D) maps of pO2, pH and Pi for multiple solution samples. This was made possible by combining a multifunctional radical probe, fast CW-EPR spectral acquisition, four-dimensional (4D) spectral-spatial image reconstruction, and spectral fitting. The experimental results of mapping pO2, pH and Pi suggest that the concept of simultaneous mapping using EPR is potentially applicable for the multifunctional measurements of a mouse tumour model.
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Affiliation(s)
- Akihiro Taguchi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
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Merging Preclinical EPR Tomography with other Imaging Techniques. Cell Biochem Biophys 2019; 77:187-196. [PMID: 31440878 PMCID: PMC6742609 DOI: 10.1007/s12013-019-00880-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/30/2019] [Indexed: 12/21/2022]
Abstract
This paper presents a survey of electron paramagnetic resonance (EPR) image registration. Image registration is the process of overlaying images (two or more) of the same scene taken at different times, from different viewpoints and/or different techniques. EPR-imaging (EPRI) techniques belong to the functional-imaging modalities and therefore suffer from a lack of anatomical reference which is mandatory in preclinical imaging. For this reason, it is necessary to merging EPR images with other modalities which allow for obtaining anatomy images. Methodological analysis and review of the literature were done, providing a summary for developing a good foundation for research study in this field which is crucial in understanding the existing levels of knowledge. Out of these considerations, the aim of this paper is to enhance the scientific community’s understanding of the current status of research in EPR preclinical image registration and also communicate to them the contribution of this research in the field of image processing.
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Yokoyama T, Taguchi A, Kubota H, Stewart NJ, Matsumoto S, Kirilyuk IA, Hirata H. Simultaneous T 2* mapping of 14N- and 15N-labeled dicarboxy-PROXYLs using CW-EPR-based single-point imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 305:122-130. [PMID: 31271927 DOI: 10.1016/j.jmr.2019.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/21/2019] [Accepted: 06/24/2019] [Indexed: 06/09/2023]
Abstract
This article reports a method of simultaneous T2* mapping of 14N- and 15N-labeled dicarboxy-PROXYLs using 750-MHz continuous-wave electron paramagnetic resonance (CW-EPR) imaging. To separate the spectra of 14N- and 15N-labeled dicarboxy-PROXYLs under magnetic field gradients, an optimization problem for spectral projections was formulated with the spatial total variation as a regularization term and solved using a local search based on the gradient descent algorithm. Using the single-point imaging (SPI) method with spectral projections of each radical, simultaneous T2* mapping was performed for solution samples. Simultaneous T2* mapping enabled visualization of the response of T2* values to the level of dissolved oxygen in the solution. Simultaneous T2* mapping applied to a mouse tumor model demonstrated the feasibility of the reported method for potential application to in vivo oxygenation imaging.
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Affiliation(s)
- Takahito Yokoyama
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Akihiro Taguchi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Harue Kubota
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Neil J Stewart
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Igor A Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, 9, Ac. Lavrentieva Ave., Novosibirsk 630090, Russia
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan.
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11
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Samouilov A, Ahmad R, Boslett J, Liu X, Petryakov S, Zweier JL. Development of a fast-scan EPR imaging system for highly accelerated free radical imaging. Magn Reson Med 2019; 82:842-853. [PMID: 31020713 DOI: 10.1002/mrm.27759] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/07/2019] [Accepted: 03/11/2019] [Indexed: 01/01/2023]
Abstract
PURPOSE In continuous wave EPR imaging, the acquisition of high-quality images was previously limited by the requisite long acquisition times of each image projection that was typically greater than 1 second. To accelerate the process of image acquisition facilitating greater numbers of projections and higher image resolution, instrumentation was developed to greatly accelerate the magnetic field scan that is used to obtain each EPR image projection. METHODS A low-inductance solenoidal coil for field scanning was used along with a spherical solenoid air core magnet, and scans were driven by triangular symmetric waves, allowing forward and reverse spectrum acquisition as rapid as 3.8 ms. The uniform distribution of projections was used to optimize the contribution of projections for 3D image reconstruction. RESULTS Using this fast-scan EPR system, high-quality EPR images of phantoms and perfused rat hearts were performed using trityl or nanoparticulate LiNcBuO (lithium octa-n-butoxy-substituted naphthalocyanine) probes with fast-scan EPR imaging at L-band, achieving spatial resolutions of up to 250 micrometers in 1 minute. CONCLUSION Fast-scan EPR imaging can greatly facilitate the efficient and precise mapping of the spatial distribution of free radical and other paramagnetic probes in living systems.
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Affiliation(s)
- Alexandre Samouilov
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - Rizwan Ahmad
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - James Boslett
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - Xiaoping Liu
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - Sergey Petryakov
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Jay L Zweier
- Davis Heart and Lung Research Institute and the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
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Komarov DA, Ichikawa Y, Yamamoto K, Stewart NJ, Matsumoto S, Yasui H, Kirilyuk IA, Khramtsov VV, Inanami O, Hirata H. In Vivo Extracellular pH Mapping of Tumors Using Electron Paramagnetic Resonance. Anal Chem 2018; 90:13938-13945. [PMID: 30372035 DOI: 10.1021/acs.analchem.8b03328] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
An electron paramagnetic resonance (EPR)-based method for noninvasive three-dimensional extracellular pH mapping was developed using a pH-sensitive nitroxyl radical as an exogenous paramagnetic probe. Fast projection scanning with a constant magnetic field sweep enabled the acquisition of four-dimensional (3D spatial +1D spectral) EPR images within 7.5 min. Three-dimensional maps of pH were reconstructed by processing the pH-dependent spectral information on the images. To demonstrate the proposed method of pH mapping, the progress of extracellular acidosis in tumor-bearing mouse legs was studied. Furthermore, extracellular pH mapping was used to visualize the spatial distribution of acidification in different tumor xenograft mouse models of human-derived pancreatic ductal adenocarcinoma cells. The proposed EPR-based pH mapping method enabled quantitative visualization of regional changes in extracellular pH associated with altered tumor metabolism.
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Affiliation(s)
- Denis A Komarov
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology , Hokkaido University , North 14, West 9 , Kita-ku, Sapporo , 060-0814 , Japan
| | - Yuki Ichikawa
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology , Hokkaido University , North 14, West 9 , Kita-ku, Sapporo , 060-0814 , Japan
| | - Kumiko Yamamoto
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine , Hokkaido University , North 18, West 9 , Kita-ku, Sapporo , 060-0818 , Japan
| | - Neil J Stewart
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology , Hokkaido University , North 14, West 9 , Kita-ku, Sapporo , 060-0814 , Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology , Hokkaido University , North 14, West 9 , Kita-ku, Sapporo , 060-0814 , Japan
| | - Hironobu Yasui
- Central Institute of Isotope Science , Hokkaido University , North 15, West 7 , Kita-ku,Sapporo , 060-0815 , Japan
| | - Igor A Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry , 9, Ac. Lavrentieva Ave. , Novosibirsk , 630090 , Russia
| | - Valery V Khramtsov
- Department of Biochemistry and In Vivo Multifunctional Magnetic Resonance Center , West Virginia University, Robert C. Byrd Health Sciences Center , 1 Medical Center Drive , Morgantown , West Virginia 26506 , United States
| | - Osamu Inanami
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine , Hokkaido University , North 18, West 9 , Kita-ku, Sapporo , 060-0818 , Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology , Hokkaido University , North 14, West 9 , Kita-ku, Sapporo , 060-0814 , Japan
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13
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Sato-Akaba H, Emoto MC, Hirata H, Fujii HG. Design and testing of a 750MHz CW-EPR digital console for small animal imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 284:48-58. [PMID: 28961477 DOI: 10.1016/j.jmr.2017.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/15/2017] [Accepted: 09/16/2017] [Indexed: 05/12/2023]
Abstract
This paper describes the development of a digital console for three-dimensional (3D) continuous wave electron paramagnetic resonance (CW-EPR) imaging of a small animal to improve the signal-to-noise ratio and lower the cost of the EPR imaging system. A RF generation board, an RF acquisition board and a digital signal processing (DSP) & control board were built for the digital EPR detection. Direct sampling of the reflected RF signal from a resonator (approximately 750MHz), which contains the EPR signal, was carried out using a band-pass subsampling method. A direct automatic control system to reduce the reflection from the resonator was proposed and implemented in the digital EPR detection scheme. All DSP tasks were carried out in field programmable gate array ICs. In vivo 3D imaging of nitroxyl radicals in a mouse's head was successfully performed.
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Affiliation(s)
- Hideo Sato-Akaba
- Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
| | - Miho C Emoto
- Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido 060-8556, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido 060-0814, Japan
| | - Hirotada G Fujii
- Center for Medical Education, Sapporo Medical University, Sapporo, Hokkaido 060-8556, Japan
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14
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Amida T, Nakaoka R, Komarov DA, Yamamoto K, Inanami O, Matsumoto S, Hirata H. A 750-MHz Electronically Tunable Resonator Using Microstrip Line Couplers for Electron Paramagnetic Resonance Imaging of a Mouse Tumor-Bearing Leg. IEEE Trans Biomed Eng 2017; 65:1124-1132. [PMID: 28841547 DOI: 10.1109/tbme.2017.2743232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE The purpose of this work was to develop an electronically tunable resonator operating at 750 MHz for continuous-wave electron paramagnetic resonance (CW-EPR) imaging of a mouse tumor-bearing leg. METHODS The resonator had a multi-coil parallel-gap structure with a sample space of 16 mm in diameter and 20 mm in length. Microstrip line couplers were used in conjunction with varactor diodes to enable resonance frequency adjustment and to reduce the nonlinear effects of the varactor diodes. The resonator was modeled by the finite-element method and a microwave circuit simulation was performed to clarify its radiofrequency characteristics. RESULTS A tunable resonator was evaluated in terms of its resonance frequency, tunable frequency band, and conversion efficiency of the RF magnetic field. The developed resonator provided a tunable frequency band of 4 MHz at a central frequency of 747 MHz and a conversion efficiency of 34 μT/W1/2. To demonstrate the application of this tunable resonator to EPR imaging, three-dimensional EPR images of a sample solution and a mouse tumor-bearing leg were obtained. CONCLUSION The developed tunable resonator satisfied our initial requirements for in vivo EPR imaging and may be able to be further improved using the present finite-element and circuit models if any problems arise during future practical applications. SIGNIFICANCE This work may help to promote EPR imaging of tumor-bearing mice in cancer-related studies.
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15
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Komarov DA, Hirata H. Fast backprojection-based reconstruction of spectral-spatial EPR images from projections with the constant sweep of a magnetic field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 281:44-50. [PMID: 28549338 DOI: 10.1016/j.jmr.2017.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 06/07/2023]
Abstract
In this paper, we introduce a procedure for the reconstruction of spectral-spatial EPR images using projections acquired with the constant sweep of a magnetic field. The application of a constant field-sweep and a predetermined data sampling rate simplifies the requirements for EPR imaging instrumentation and facilitates the backprojection-based reconstruction of spectral-spatial images. The proposed approach was applied to the reconstruction of a four-dimensional numerical phantom and to actual spectral-spatial EPR measurements. Image reconstruction using projections with a constant field-sweep was three times faster than the conventional approach with the application of a pseudo-angle and a scan range that depends on the applied field gradient. Spectral-spatial EPR imaging with a constant field-sweep for data acquisition only slightly reduces the signal-to-noise ratio or functional resolution of the resultant images and can be applied together with any common backprojection-based reconstruction algorithm.
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Affiliation(s)
- Denis A Komarov
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan.
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16
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Kubota H, Komarov DA, Yasui H, Matsumoto S, Inanami O, Kirilyuk IA, Khramtsov VV, Hirata H. Feasibility of in vivo three-dimensional T 2* mapping using dicarboxy-PROXYL and CW-EPR-based single-point imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 30:291-298. [PMID: 28063096 DOI: 10.1007/s10334-016-0606-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/13/2016] [Accepted: 12/22/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVES The aim of this study was to demonstrate the feasibility of in vivo three-dimensional (3D) relaxation time T 2* mapping of a dicarboxy-PROXYL radical using continuous-wave electron paramagnetic resonance (CW-EPR) imaging. MATERIALS AND METHODS Isotopically substituted dicarboxy-PROXYL radicals, 3,4-dicarboxy-2,2,5,5-tetra(2H3)methylpyrrolidin-(3,4-2H2)-(1-15N)-1-oxyl (2H,15N-DCP) and 3,4-dicarboxy-2,2,5,5-tetra(2H3)methylpyrrolidin-(3,4-2H2)-1-oxyl (2H-DCP), were used in the study. A clonogenic cell survival assay was performed with the 2H-DCP radical using squamous cell carcinoma (SCC VII) cells. The time course of EPR signal intensities of intravenously injected 2H,15N-DCP and 2H-DCP radicals were determined in tumor-bearing hind legs of mice (C3H/HeJ, male, n = 5). CW-EPR-based single-point imaging (SPI) was performed for 3D T 2* mapping. RESULTS 2H-DCP radical did not exhibit cytotoxicity at concentrations below 10 mM. The in vivo half-life of 2H,15N-DCP in tumor tissues was 24.7 ± 2.9 min (mean ± standard deviation [SD], n = 5). The in vivo time course of the EPR signal intensity of the 2H,15N-DCP radical showed a plateau of 10.2 ± 1.2 min (mean ± SD) where the EPR signal intensity remained at more than 90% of the maximum intensity. During the plateau, in vivo 3D T 2* maps with 2H,15N-DCP were obtained from tumor-bearing hind legs, with a total acquisition time of 7.5 min. CONCLUSION EPR signals of 2H,15N-DCP persisted long enough after bolus intravenous injection to conduct in vivo 3D T 2* mapping with CW-EPR-based SPI.
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Affiliation(s)
- Harue Kubota
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Denis A Komarov
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Hironobu Yasui
- Central Institute of Isotope Science, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-0815, Japan
| | - Shingo Matsumoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, North 18, West 9, Kita-ku, Sapporo, 060-0818, Japan
| | - Igor A Kirilyuk
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, 9, Ac. Lavrentieva Ave., Novosibirsk, 630090, Russia
| | - Valery V Khramtsov
- Department of Biochemistry, West Virginia University, Robert C. Byrd Health Sciences Center, 1 Medical Center Drive, Morgantown, WV, 26506, USA
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo, 060-0814, Japan.
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17
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Wang X, Emoto M, Miyake Y, Itto K, Xu S, Fujii H, Hirata H, Arimoto H. Novel blood–brain barrier-permeable spin probe for in vivo electron paramagnetic resonance imaging. Bioorg Med Chem Lett 2016; 26:4947-4949. [DOI: 10.1016/j.bmcl.2016.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/18/2016] [Accepted: 09/05/2016] [Indexed: 02/03/2023]
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18
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Tadyszak K, Boś-Liedke A, Jurga J, Baranowski M, Mrówczyński R, Chlewicki W, Jurga S, Czechowski T. Overmodulation of projections as signal-to-noise enhancement method in EPR imaging. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:136-142. [PMID: 26364566 DOI: 10.1002/mrc.4330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 07/08/2015] [Accepted: 08/04/2015] [Indexed: 06/05/2023]
Abstract
A study concerning the image quality in electron paramagnetic resonance imaging in two-dimensional spatial experiments is presented. The aim of the measurements was to improve the signal-to-noise ratio (SNR) of the projections and the reconstructed image by applying modulation amplitude higher than the radical electron paramagnetic resonance linewidth. Data were gathered by applying four constant modulation amplitudes, where one was below 1/3 (Amod = 0.04 mT) of the radical linewidth (ΔBpp = 0.14 mT). Three other modulation amplitude values were used in this experiment, leading to undermodulated (Amod < 1/3 ΔBpp), partially overmodulated (Amod ~ 1/3 ΔBpp) and fully overmodulated (Amod > > 1/3 ΔBpp) projections. The advantages of an applied overmodulation condition were demonstrated in the study performed on a phantom containing four shapes of 1.25 mM water solution of 2, 2, 6, 6-tetramethyl-1-piperidinyloxyl. It was shown that even when the overmodulated reference spectrum was used in the deconvolution procedure, as well as the projection itself, the phantom shapes reconstructed as images directly correspond to those obtained in undermodulation conditions. It was shown that the best SNR of the reconstructed images is expected for the modulation amplitude close to 1/3 of the projection linewidth, which is defined as the distance from the first maximum to the last minimum of the gradient-broadened spectrum. For higher modulation amplitude, the SNR of the reconstructed image is decreased, even if the SNR of the measured projection is increased.
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Affiliation(s)
- Krzysztof Tadyszak
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61614, Poznań, Poland
| | - Agnieszka Boś-Liedke
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61614, Poznań, Poland
- Department of Medical Physics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61614, Poznań, Poland
| | - Jan Jurga
- Laboratory of EPR Tomography, Poznań University of Technology, ul. Piotrowo 3, 60965, Poznań, Poland
- noviLET, ul. Naramowicka 232, PL, 61611, Poznań, Poland
| | - Mikołaj Baranowski
- Department of Physics, Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, PL, 61614, Poznań, Poland
- noviLET, ul. Naramowicka 232, PL, 61611, Poznań, Poland
| | - Radosław Mrówczyński
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61614, Poznań, Poland
| | - Wojciech Chlewicki
- Faculty of Electrical Engineering, West Pomeranian University of Technology, al. Piastów 17, 70-310, Szczecin, Poland
- noviLET, ul. Naramowicka 232, PL, 61611, Poznań, Poland
| | - Stefan Jurga
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61614, Poznań, Poland
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, ul. Romana Maya 1, 61371, Poznań, Poland
| | - Tomasz Czechowski
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, 61614, Poznań, Poland
- Laboratory of EPR Tomography, Poznań University of Technology, ul. Piotrowo 3, 60965, Poznań, Poland
- noviLET, ul. Naramowicka 232, PL, 61611, Poznań, Poland
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19
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Czechowski T, Chlewicki W, Baranowski M, Jurga K, Szczepanik P, Szulc P, Tadyszak K, Kedzia P, Szostak M, Malinowski P, Wosinski S, Prukala W, Jurga J. Two-dimensional EPR imaging with the rapid scan and rotated magnetic field gradient. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 248:126-30. [PMID: 25442781 DOI: 10.1016/j.jmr.2014.09.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/13/2014] [Accepted: 09/23/2014] [Indexed: 05/12/2023]
Abstract
A new method for fast 2D Electron Paramagnetic Resonance Imaging (EPRI) is presented. To reduce the time of projections acquisition we propose to combine rapid scan of Zeeman magnetic field using high frequency sinusoidal modulation with simultaneously applied magnetic field gradient, whose orientation is changed at low frequency. The correctness of the method is confirmed by studies carried out on a phantom consisting of two LiPc samples. The images from the acquired data are reconstructed using iterative algorithms. The proposed method allows to reduce the image acquisition time up to 10 ms for 2D EPRI, and to detect the sinogram with infinitesimal angular step between projections.
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Affiliation(s)
- T Czechowski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland.
| | - W Chlewicki
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland; Faculty of Electrical Engineering, West Pomeranian University of Technology, 70-310 Szczecin, Poland
| | - M Baranowski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland; Department of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - K Jurga
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Szczepanik
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Szulc
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - K Tadyszak
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 14, PL 61614 Poznan, Poland
| | - P Kedzia
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - M Szostak
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Malinowski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - S Wosinski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - W Prukala
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland; Department of Organometalic Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland
| | - J Jurga
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
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20
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Takahashi W, Miyake Y, Hirata H. Artifact suppression in electron paramagnetic resonance imaging of (14)N- and (15)N-labeled nitroxyl radicals with asymmetric absorption spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 247:31-37. [PMID: 25233111 DOI: 10.1016/j.jmr.2014.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 08/01/2014] [Accepted: 08/04/2014] [Indexed: 06/03/2023]
Abstract
This article describes an improved method for suppressing image artifacts in the visualization of (14)N- and (15)N-labeled nitroxyl radicals in a single image scan using electron paramagnetic resonance (EPR). The purpose of this work was to solve the problem of asymmetric EPR absorption spectra in spectral processing. A hybrid function of Gaussian and Lorentzian lineshapes was used to perform spectral line-fitting to successfully separate the two kinds of nitroxyl radicals. This approach can process the asymmetric EPR absorption spectra of the nitroxyl radicals being measured, and can suppress image artifacts due to spectral asymmetry. With this improved visualization method and a 750-MHz continuous-wave EPR imager, a temporal change in the distributions of a two-phase paraffin oil and water/glycerin solution system was visualized using lipophilic and hydrophilic nitroxyl radicals, i.e., 2-(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxazolidinyloxy (16-DOXYL stearic acid) and 4-hydroxyl-2,2,6,6-tetramethylpiperidine-d17-1-(15)N-1-oxyl (TEMPOL-d17-(15)N). The results of the two-phase separation experiment verified that reasonable artifact suppression could be achieved by the present method that deals with asymmetric absorption spectra in the EPR imaging of (14)N- and (15)N-labeled nitroxyl radicals.
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Affiliation(s)
- Wataru Takahashi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Yusuke Miyake
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan.
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21
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Czechowski T, Chlewicki W, Baranowski M, Jurga K, Szczepanik P, Szulc P, Kedzia P, Szostak M, Malinowski P, Wosinski S, Prukala W, Jurga J. Two-dimensional spectral-spatial EPR imaging with the rapid scan and modulated magnetic field gradient. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 243:1-7. [PMID: 24705409 DOI: 10.1016/j.jmr.2014.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 06/03/2023]
Abstract
A new method for fast spectral-spatial electron paramagnetic resonance imaging (EPRI) is presented. To reduce the time of projections acquisition we propose to combine rapid scan of Zeeman magnetic field using high frequency sinusoidal modulation with simultaneously applied magnetic field gradients, whose amplitude is modulated at low frequency. The correctness of the method is confirmed by studies carried out on a phantom consisting of two LiPc samples. The spectral-spatial images from the acquired data are reconstructed using iterative algorithms. The proposed method allows to acquire the spectral-spatial image with 800 projections at 200ms.
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Affiliation(s)
- T Czechowski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland.
| | - W Chlewicki
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland; Faculty of Electrical Engineering, West Pomeranian University of Technology, 70-310 Szczecin, Poland
| | - M Baranowski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland; Department of Physics, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - K Jurga
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Szczepanik
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Szulc
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Kedzia
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - M Szostak
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - P Malinowski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - S Wosinski
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
| | - W Prukala
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland; Department of Organometallic Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland
| | - J Jurga
- Laboratory of EPR Tomography, Poznan University of Technology, 60-965 Poznan, Poland
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22
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Goodwin J, Yachi K, Nagane M, Yasui H, Miyake Y, Inanami O, Bobko AA, Khramtsov VV, Hirata H. In vivo tumour extracellular pH monitoring using electron paramagnetic resonance: the effect of X-ray irradiation. NMR IN BIOMEDICINE 2014; 27:453-458. [PMID: 24470192 PMCID: PMC3960982 DOI: 10.1002/nbm.3081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 01/02/2014] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
The in vivo quantification of extracellular pH (pHe ) in tumours may provide a useful biomarker for tumour cell metabolism. In this study, we assessed the viability of continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy with a pH-sensitive nitroxide for the measurement of extracellular tumour pH in a mouse model. CW-EPR spectroscopy (750 MHz) of C3H HeJ mice hind leg squamous cell tumour was performed after intravenous tail vein injection of pH-sensitive nitroxide (R-SG, 2-(4-((2-(4-amino-4-carboxybutanamido)-3-(carboxymethylamino)-3-oxoproylthio)methyl)phenyl)-4-pyrrolidino-2,5,5-triethyl-2,5-dihydro-1Н-imidazol-1-oxyl) during stages of normal tumour growth and in response to a single 10-Gy dose of X-ray irradiation. An inverse relationship was observed between tumour volume and pHe value, whereby, during normal tumour growth, a constant reduction in pHe was observed. This relationship was disrupted by X-ray irradiation and, from 2-3 days post-exposure, a transitory increase in pHe was observed. In this study, we demonstrated the viability of CW-EPR spectroscopy using R-SG nitroxide to obtain high-sensitivity pH measurements in a mouse tumour model with an accuracy of <0.1 pH units. In addition, the measured changes in pHe in response to X-ray irradiation suggest that this may offer a useful method for the assessment of the physiological change in response to existing and novel cancer therapies.
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Affiliation(s)
- Jonathan Goodwin
- Department of Diagnostic Radiology, Hokkaido University Hospital, Sapporo, Japan
- Division of UltraHigh Field MRI, Iwate Medical University, Yahaba, Iwate, Japan
| | - Katsuya Yachi
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Masaki Nagane
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yusuke Miyake
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Andrey A. Bobko
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, The Ohio State University, Columbus, OH, USA
| | - Valery V. Khramtsov
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, The Ohio State University, Columbus, OH, USA
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Japan
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23
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Wang X, Emoto M, Sugimoto A, Miyake Y, Itto K, Amasaka M, Xu S, Hirata H, Fujii H, Arimoto H. Synthesis of 15N-labeled 4-oxo-2,2,6,6-tetraethylpiperidine nitroxide for EPR brain imaging. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.02.063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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24
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Enomoto A, Hirata H. Parallel image-acquisition in continuous-wave electron paramagnetic resonance imaging with a surface coil array: Proof-of-concept experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 239:29-33. [PMID: 24374749 DOI: 10.1016/j.jmr.2013.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/03/2013] [Accepted: 12/04/2013] [Indexed: 06/03/2023]
Abstract
This article describes a feasibility study of parallel image-acquisition using a two-channel surface coil array in continuous-wave electron paramagnetic resonance (CW-EPR) imaging. Parallel EPR imaging was performed by multiplexing of EPR detection in the frequency domain. The parallel acquisition system consists of two surface coil resonators and radiofrequency (RF) bridges for EPR detection. To demonstrate the feasibility of this method of parallel image-acquisition with a surface coil array, three-dimensional EPR imaging was carried out using a tube phantom. Technical issues in the multiplexing method of EPR detection were also clarified. We found that degradation in the signal-to-noise ratio due to the interference of RF carriers is a key problem to be solved.
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Affiliation(s)
- Ayano Enomoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan.
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25
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Enomoto A, Emoto M, Fujii H, Hirata H. Four-channel surface coil array for sequential CW-EPR image acquisition. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 234:21-29. [PMID: 23832070 DOI: 10.1016/j.jmr.2013.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/05/2013] [Accepted: 06/10/2013] [Indexed: 06/02/2023]
Abstract
This article describes a four-channel surface coil array to increase the area of visualization for continuous-wave electron paramagnetic resonance (CW-EPR) imaging. A 776-MHz surface coil array was constructed with four independent surface coil resonators and three kinds of switches. Control circuits for switching the resonators were also built to sequentially perform EPR image acquisition for each resonator. The resonance frequencies of the resonators were shifted using PIN diode switches to decouple the inductively coupled coils. To investigate the area of visualization with the surface coil array, three-dimensional EPR imaging was performed using a glass cell phantom filled with a solution of nitroxyl radicals. The area of visualization obtained with the surface coil array was increased approximately 3.5-fold in comparison to that with a single surface coil resonator. Furthermore, to demonstrate the applicability of this surface coil array to animal imaging, three-dimensional EPR imaging was performed in a living mouse with an exogenously injected nitroxyl radical imaging agent.
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Affiliation(s)
- Ayano Enomoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan
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26
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Fujii HG, Sato-Akaba H, Emoto MC, Itoh K, Ishihara Y, Hirata H. Noninvasive mapping of the redox status in septic mouse by in vivo electron paramagnetic resonance imaging. Magn Reson Imaging 2013; 31:130-8. [DOI: 10.1016/j.mri.2012.06.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 06/19/2012] [Indexed: 12/21/2022]
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27
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Miyake Y, Wang X, Amasaka M, Itto K, Xu S, Arimoto H, Fujii H, Hirata H. Simultaneous Imaging of an Enantiomer Pair by Electron Paramagnetic Resonance Using Isotopic Nitrogen Labeling. Anal Chem 2012; 85:985-90. [DOI: 10.1021/ac302710m] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yusuke Miyake
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
| | - Xiaolei Wang
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Mitsuo Amasaka
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
| | - Kaori Itto
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Shu Xu
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Hirokazu Arimoto
- Department
of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai
980-8577, Japan
| | - Hirotada Fujii
- Department
of Arts and Sciences, Center for Medical Education, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo
060-8556, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics,
Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo,
060-0814, Japan
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28
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Palmer J, Potter L, Johnson D, Zweier J, Ahmad R. Dual-scan acquisition for accelerated continuous-wave EPR oximetry. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 222:53-58. [PMID: 22820009 PMCID: PMC3423522 DOI: 10.1016/j.jmr.2012.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 05/11/2012] [Accepted: 05/26/2012] [Indexed: 06/01/2023]
Abstract
Statistical analysis reveals that, given a fixed acquisition time, linewidth (and thus pO(2)) can be more precisely determined from multiple scans with different modulation amplitudes and sweep widths than from a single-scan. For a Lorentzian lineshape and an unknown but spatially uniform modulation amplitude, the analysis suggests the use of two scans, each occupying half of the total acquisition time. We term this mode of scanning as dual-scan acquisition. For unknown linewidths in a range [Γ(min), Γ(max)], practical guidelines are provided for selecting the modulation amplitude and sweep width for each dual-scan component. Following these guidelines can allow for a 3-4 times reduction in spectroscopic acquisition time versus an optimized single-scan, without requiring hardware modifications. Findings are experimentally verified using L-band spectroscopy with an oxygen-sensitive particulate probe.
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Affiliation(s)
- J. Palmer
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - L.C. Potter
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - D.H. Johnson
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - J.L. Zweier
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - R. Ahmad
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
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29
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Koda S, Goodwin J, Khramtsov VV, Fujii H, Hirata H. Electron paramagnetic resonance-based pH mapping using spectral-spatial imaging of sequentially scanned spectra. Anal Chem 2012; 84:3833-7. [PMID: 22424377 PMCID: PMC3366692 DOI: 10.1021/ac203415w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of electron paramagnetic resonance (EPR)-based mapping of pH is an important advancement for the field of diagnostic imaging. The ability to accurately quantify pH change in vivo and monitor spatial distribution is desirable for the assessment of a number of pathological conditions in the human body as well as the monitoring of treatment response. In this work we introduce a method for EPR-based pH mapping utilizing a method of spectral-spatial imaging of sequentially scanned spectra to decrease the missing gradient rotation angle, without increasing the spatial field of view. Repeated in vitro measurements of pH phantom tubes demonstrated higher precision measurements of the hyperfine coupling constant (HFC) compared to previous EPR-based methods, resulting in mean pH values accurate to less than 0.1 pH across a range of physiologically observed values.
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Affiliation(s)
- Shunichi Koda
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
| | - Jonathan Goodwin
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
| | - Valery V. Khramtsov
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, United States of America
| | - Hirotada Fujii
- Department of Arts and Sciences, Center for Medical Education, Sapporo Medical University, Sapporo 060-8556, Japan
| | - Hiroshi Hirata
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
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30
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Chen Z, Reyes LA, Johnson DH, Velayutham M, Yang C, Samouilov A, Zweier JL. Fast gated EPR imaging of the beating heart: spatiotemporally resolved 3D imaging of free-radical distribution during the cardiac cycle. Magn Reson Med 2012; 69:594-601. [PMID: 22473660 DOI: 10.1002/mrm.24250] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/13/2012] [Accepted: 02/20/2012] [Indexed: 11/06/2022]
Abstract
In vivo or ex vivo electron paramagnetic resonance imaging (EPRI) is a powerful technique for determining the spatial distribution of free radicals and other paramagnetic species in living organs and tissues. However, applications of EPRI have been limited by long projection acquisition times and the consequent fact that rapid gated EPRI was not possible. Hence in vivo EPRI typically provided only time-averaged information. In order to achieve direct gated EPRI, a fast EPR acquisition scheme was developed to decrease EPR projection acquisition time down to 10-20 ms, along with corresponding software and instrumentation to achieve fast gated EPRI of the isolated beating heart with submillimeter spatial resolution in as little as 2-3 min. Reconstructed images display temporal and spatial variations of the free-radical distribution, anatomical structure, and contractile function within the rat heart during the cardiac cycle.
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Affiliation(s)
- Zhiyu Chen
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
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31
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Ahmad R, Som S, Johnson DH, Zweier JL, Kuppusamy P, Potter LC. Multisite EPR oximetry from multiple quadrature harmonics. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 214:135-143. [PMID: 22154283 PMCID: PMC3257390 DOI: 10.1016/j.jmr.2011.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/24/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
Multisite continuous wave (CW) electron paramagnetic resonance (EPR) oximetry using multiple quadrature field modulation harmonics is presented. First, a recently developed digital receiver is used to extract multiple harmonics of field modulated projection data. Second, a forward model is presented that relates the projection data to unknown parameters, including linewidth at each site. Third, a maximum likelihood estimator of unknown parameters is reported using an iterative algorithm capable of jointly processing multiple quadrature harmonics. The data modeling and processing are applicable for parametric lineshapes under nonsaturating conditions. Joint processing of multiple harmonics leads to 2-3-fold acceleration of EPR data acquisition. For demonstration in two spatial dimensions, both simulations and phantom studies on an L-band system are reported.
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Affiliation(s)
- R Ahmad
- Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
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32
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Emoto M, Mito F, Yamasaki T, Yamada KI, Sato-Akaba H, Hirata H, Fujii H. A novel ascorbic acid-resistant nitroxide in fat emulsion is an efficient brain imaging probe forin vivoEPR imaging of mouse. Free Radic Res 2011; 45:1325-32. [DOI: 10.3109/10715762.2011.618499] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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33
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Enomoto A, Hirata H. Sequential CW-EPR image acquisition with 760-MHz surface coil array. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 209:244-249. [PMID: 21320789 DOI: 10.1016/j.jmr.2011.01.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 01/19/2011] [Accepted: 01/19/2011] [Indexed: 05/30/2023]
Abstract
This paper describes the development of a surface coil array that consists of two inductively coupled surface-coil resonators, for use in continuous-wave electron paramagnetic resonance (CW-EPR) imaging at 760 MHz. To make sequential EPR image acquisition possible, we decoupled the surface coils using PIN-diode switches, to enable the shifting of the resonators resonance frequency by more than 200 MHz. To assess the effectiveness of the surface coil array in CW-EPR imaging, two-dimensional images of a solution of nitroxyl radicals were measured with the developed coil array. Compared to equivalent single coil acquired images, we found the visualized area to be extended approximately 2-fold when using the surface coil array. The ability to visualize larger regions of interest through the use of a surface coil array, may offer great potential in future EPR imaging studies.
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Affiliation(s)
- Ayano Enomoto
- Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, Kita-ku, Sapporo 060-0814, Japan
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34
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Ahmad R, Som S, Kesselring E, Kuppusamy P, Zweier JL, Potter LC. Digital detection and processing of multiple quadrature harmonics for EPR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:322-31. [PMID: 20971667 PMCID: PMC2993834 DOI: 10.1016/j.jmr.2010.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 09/24/2010] [Accepted: 09/24/2010] [Indexed: 05/12/2023]
Abstract
A quadrature digital receiver and associated signal estimation procedure are reported for L-band electron paramagnetic resonance (EPR) spectroscopy. The approach provides simultaneous acquisition and joint processing of multiple harmonics in both in-phase and out-of-phase channels. The digital receiver, based on a high-speed dual-channel analog-to-digital converter, allows direct digital down-conversion with heterodyne processing using digital capture of the microwave reference signal. Thus, the receiver avoids noise and nonlinearity associated with analog mixers. Also, the architecture allows for low-Q anti-alias filtering and does not require the sampling frequency to be time-locked to the microwave reference. A noise model applicable for arbitrary contributions of oscillator phase noise is presented, and a corresponding maximum-likelihood estimator of unknown parameters is also reported. The signal processing is applicable for Lorentzian lineshape under nonsaturating conditions. The estimation is carried out using a convergent iterative algorithm capable of jointly processing the in-phase and out-of-phase data in the presence of phase noise and unknown microwave phase. Cramér-Rao bound analysis and simulation results demonstrate a significant reduction in linewidth estimation error using quadrature detection, for both low and high values of phase noise. EPR spectroscopic data are also reported for illustration.
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Affiliation(s)
- R Ahmad
- Center of Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
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35
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Ahmad R, Caia G, Potter L, Petryakov S, Kuppusamy P, Zweier J. In vivo multisite oximetry using EPR-NMR coimaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:69-77. [PMID: 20850361 PMCID: PMC2956866 DOI: 10.1016/j.jmr.2010.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 05/19/2010] [Accepted: 08/17/2010] [Indexed: 05/29/2023]
Abstract
Coimaging employing electron paramagnetic resonance (EPR) imaging and MRI is used for rapid in vivo oximetry conducted simultaneously across multiple organs of a mouse. A recently developed hybrid EPR-NMR coimaging instrument is used for both EPR and NMR measurements. Oxygen sensitive particulate EPR probe is implanted in small localized pockets, called sites, across multiple regions of a live mouse. Three dimensional MRI is used to generate anatomic visualization, providing precise locations of implant sites. The pO₂ values, one for every site, are then estimated from EPR measurements. To account for radio frequency (RF) phase inhomogeneities inside a large resonator carrying a lossy sample, a generalization of an existing EPR data model is proposed. Utilization of known spectral lineshape, sparse distribution, and known site locations reduce the EPR data collection by more than an order of magnitude over a conventional spectral-spatial imaging, enhancing the feasibility of in vivo EPR oximetry for clinically relevant models.
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Affiliation(s)
- R. Ahmad
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - G. Caia
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - L.C. Potter
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - S. Petryakov
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - P. Kuppusamy
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - J.L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH, 43210, USA
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36
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Fujii H, Sato-Akaba H, Kawanishi K, Hirata H. Mapping of redox status in a brain-disease mouse model by three-dimensional EPR imaging. Magn Reson Med 2010; 65:295-303. [DOI: 10.1002/mrm.22598] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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