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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 2024:10.1007/s11307-024-01924-y. [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] [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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Tseytlin O, O'Connell R, Sivashankar V, Bobko AA, Tseytlin M. Rapid Scan EPR Oxygen Imaging in Photoactivated Resin Used for Stereolithographic 3D Printing. 3D PRINTING AND ADDITIVE MANUFACTURING 2021; 8:358-365. [PMID: 34977276 PMCID: PMC8713732 DOI: 10.1089/3dp.2020.0170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Oxygen plays a critical role in the photopolymerization process resulting in the formation of solid structures from liquid resins during three-dimensional (3D) printing: it acts as a polymerization inhibitor. Upon exposure to light, oxygen is depleted. As a result, the polymerization process becomes activated. Electron paramagnetic resonance (EPR) imaging is described as a tool to visualize changes in oxygen distribution caused by light exposure. This nondestructive method uses radio waves and, therefore, is not constrained by optical opacity offering greater penetrating depth. Three proof-of-principle imaging experiments were demonstrated: (1) spatial propagation of the photopolymerization process; (2) oxygen depletion as a result of postcuring; and (3) oxygen visualization in a 3D printed spiral model. Commercial stereolithography (SLA) resin was used in these experiments. Lithium octa-n-butoxynaphthalocyanine (LiNc-BuO) probe was mixed with the resin to permit oxygen imaging. Li-naphthalocyanine probes are routinely used in various EPR applications because of their long-term stability and high functional sensitivity to oxygen. In this study, we demonstrate that EPR imaging has the potential to become a powerful visualization tool in the development of 3D printing technology, including bioprinting and tissue engineering.
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Affiliation(s)
- Oxana Tseytlin
- Biochemistry Department, West Virginia University, Morgantown, West Virginia, USA
- In Vivo Multifunctional Magnetic Resonance Center at Robert C. Byrd Health Sciences Center, and West Virginia University, Morgantown, West Virginia, USA
| | - Ryan O'Connell
- Biochemistry Department, West Virginia University, Morgantown, West Virginia, USA
- In Vivo Multifunctional Magnetic Resonance Center at Robert C. Byrd Health Sciences Center, and West Virginia University, Morgantown, West Virginia, USA
| | - Vignesh Sivashankar
- Statler College of Engineering and Mineral Resources, West Virginia University, Morgantown, West Virginia, USA
| | - Andrey A. Bobko
- Biochemistry Department, West Virginia University, Morgantown, West Virginia, USA
- In Vivo Multifunctional Magnetic Resonance Center at Robert C. Byrd Health Sciences Center, and West Virginia University, Morgantown, West Virginia, USA
| | - Mark Tseytlin
- Biochemistry Department, West Virginia University, Morgantown, West Virginia, USA
- In Vivo Multifunctional Magnetic Resonance Center at Robert C. Byrd Health Sciences Center, and West Virginia University, Morgantown, West Virginia, USA
- West Virginia University Cancer Institute, Morgantown, West Virginia, USA
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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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Tseytlin O, Bobko AA, Tseytlin M. Rapid Scan EPR imaging as a Tool for Magnetic Field Mapping. APPLIED MAGNETIC RESONANCE 2020; 51:1117-1124. [PMID: 33642700 PMCID: PMC7909464 DOI: 10.1007/s00723-020-01238-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/24/2020] [Indexed: 06/05/2023]
Abstract
Functional four-dimensional spectral-spatial electron paramagnetic imaging (EPRI) is routinely used in biomedical research. Positions and widths of EPR lines in the spectral dimension report oxygen partial pressure, pH, and other important parameters of the tissue microenvironment. Images are measured in the homogeneous external magnetic field. An application of EPRI is proposed in which the field is perturbed by a magnetized object. A proof-of-concept imaging experiment was conducted, which permitted visualization of the magnetic field created by this object. A single-line lithium octa-n-butoxynaphthalocyanine spin probe was used in the experiment. The spectral position of the EPR line directly measured the strength of the perturbation field with spatial resolution. A three-dimensional magnetic field map was reconstructed as a result. Several applications of this technology can be anticipated. First is EPRI/MPI co-registration, where MPI is an emerging magnetic particle imaging technique. Second, EPRI can be an alternative to magnetic field cameras that are used for the development of high-end permanent magnets and their assemblies, consumer electronics, and industrial sensors. Besides the high resolution of magnetic field readings, EPR probes can be placed in the internal areas of various assemblies that are not accessible by the standard sensors. Third, EPRI can be used to develop systems for magnetic manipulation of cell cultures.
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Affiliation(s)
- Oxana Tseytlin
- Department of Biochemistry, West Virginia University,
Morgantown, WV 26506, USA
- In Vivo Multifunctional Magnetic Resonance center at Robert
C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506,
USA
| | - Andrey A. Bobko
- Department of Biochemistry, West Virginia University,
Morgantown, WV 26506, USA
- In Vivo Multifunctional Magnetic Resonance center at Robert
C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506,
USA
| | - Mark Tseytlin
- Department of Biochemistry, West Virginia University,
Morgantown, WV 26506, USA
- West Virginia University Cancer Institute, Morgantown, WV
26506, USA
- In Vivo Multifunctional Magnetic Resonance center at Robert
C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV 26506,
USA
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Komarov DA, Samouilov A, Ahmad R, Zweier JL. Algebraic reconstruction of 3D spatial EPR images from high numbers of noisy projections: An improved image reconstruction technique for high resolution fast scan EPR imaging. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 319:106812. [PMID: 32966948 PMCID: PMC7554188 DOI: 10.1016/j.jmr.2020.106812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/05/2020] [Accepted: 08/21/2020] [Indexed: 06/11/2023]
Abstract
A novel method for reconstructing 3D spatial EPR images from large numbers of noisy projections was developed that minimizes mean square error between the experimental projections and those from the reconstructed image. The method utilizes raw projection data and zero gradient spectrum to account for EPR line shape and hyperfine structure of the paramagnetic probe without the need for deconvolution techniques that are poorly suited for processing of high noise projections. A numerical phantom was reconstructed for method validation. Reconstruction time for the matrix of 1283 voxels and 16,384 noiseless projections was 4.6 min for a single iteration. The algorithm converged quickly, reaching R2 ~ 0.99975 after the very first iteration. An experimental phantom sample with nitroxyl radical was measured. With 16,384 projections and a field gradient of 8 G/cm, resolutions of 0.4 mm were achieved for a cubical area of 25 × 25 × 25 mm3. Reconstruction was sufficiently fast and memory efficient making it suitable for applications with large 3D matrices and fully determined system of equations. The developed algorithm can be used with any gradient distribution and does not require adjustable filter parameters that makes for simple application. A thorough analysis of the strengths and limitations of this method for 3D spatial EPR imaging is provided.
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Affiliation(s)
- Denis A Komarov
- Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Alexandre Samouilov
- Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Rizwan Ahmad
- Department of Biomedical Engineering and the EPR Center, College of Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Jay L Zweier
- Department of Internal Medicine, Division of Cardiovascular Medicine, and the EPR Center, Davis Heart & Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; Department of Biomedical Engineering and the EPR Center, College of Engineering, The Ohio State University, Columbus, OH 43210, USA.
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