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Wehbi M, Mignion L, Joudiou N, Harkemanne E, Gallez B. Highly Sensitive Detection of Melanin in Melanomas Using Multi-harmonic Low Frequency EPR. Mol Imaging Biol 2024; 26:484-494. [PMID: 38519805 PMCID: PMC11211186 DOI: 10.1007/s11307-024-01911-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/08/2024] [Accepted: 03/18/2024] [Indexed: 03/25/2024]
Abstract
PURPOSE Low frequency EPR can noninvasively detect endogenous free radical melanin in melanocytic skin lesions and could potentially discriminate between benign atypical nevi and malignant melanoma lesions. We recently succeeded in demonstrating the ability of clinical EPR to noninvasively detect the endogenous melanin free radical in skin lesions of patients. However, the signal-to-noise ratio (SNR) was extremely low warranting further research to boost the sensitivity of detection. In the present study, we assessed the performance of a clinical EPR system with the capability to perform multi-harmonic (MH) analysis for the detection of melanin. PROCEDURES The sensitivity of MH-EPR was compared with a classical continuous wave (CW)-EPR (1st harmonic) detection in vitro in melanin phantoms, in vivo in melanoma models with cells implanted in the skin, in lymph nodes and having colonized the lungs, and finally on phantoms placed at the surface of human skin. RESULTS In vitro, we observed an increase in SNR by a factor of 10 in flat melanin phantoms when using MH analysis compared to CW combined with an increase in modulation amplitude. In B16 melanomas having grown in the skin of hairless mice, we observed a boost in sensitivity in vivo similar to that observed in vitro with the capability to detect melanoma cells at an earlier stage of development. MH-EPR was also able to detect non-invasively the melanin signal coming from melanoma cells present in lymph nodes as well as in lungs. We also observed a boost of sensitivity using phantoms of melanin placed at the surface of human skin. CONCLUSIONS Overall, our results are paving the way for new clinical trials that will use MH clinical EPR for the characterization of pigmented skin lesions.
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Affiliation(s)
- Mohammad Wehbi
- Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Université Catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Lionel Mignion
- Nuclear and Electron Spin Technologies (NEST) Platform, Louvain Drug Research Institute, Université Catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Nicolas Joudiou
- Nuclear and Electron Spin Technologies (NEST) Platform, Louvain Drug Research Institute, Université Catholique de Louvain (UCLouvain), Brussels, Belgium
| | - Evelyne Harkemanne
- Dermatology Department, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Bernard Gallez
- Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Université Catholique de Louvain (UCLouvain), Brussels, Belgium.
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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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Kato K, Yasui H, Sato-Akaba H, Emoto MC, Fujii HG, Kmiec MM, Kuppusamy P, Mizuno Y, Kuge Y, Nagane M, Yamashita T, Inanami O. Feasibility study of multimodal imaging for redox status and glucose metabolism in tumor. Free Radic Biol Med 2024; 218:57-67. [PMID: 38574976 DOI: 10.1016/j.freeradbiomed.2024.03.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/17/2024] [Accepted: 03/30/2024] [Indexed: 04/06/2024]
Abstract
Understanding the tumor redox status is important for efficient cancer treatment. Here, we noninvasively detected changes in the redox environment of tumors before and after cancer treatment in the same individuals using a novel compact and portable electron paramagnetic resonance imaging (EPRI) device and compared the results with glycolytic information obtained through autoradiography using 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG). Human colon cancer HCT116 xenografts were used in the mice. We used 3-carbamoyl-PROXYL (3CP) as a paramagnetic and redox status probe for the EPRI of tumors. The first EPRI was followed by the intraperitoneal administration of buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, or X-ray irradiation of the tumor. A second EPRI was performed on the following day. Autoradiography was performed after the second EPRI. After imaging, the tumor sections were evaluated by histological analysis and the amount of reducing substances in the tumor was measured. BSO treatment and X-ray irradiation significantly decreased the rate of 3CP reduction in tumors. Redox maps of tumors obtained from EPRI can be compared with tissue sections of approximately the same cross section. BSO treatment reduced glutathione levels in tumors, whereas X-ray irradiation did not alter the levels of any of the reducing substances. Comparison of the redox map with the autoradiography of [18F]FDG revealed that regions with high reducing power in the tumor were active in glucose metabolism; however, this correlation disappeared after X-ray irradiation. These results suggest that the novel compact and portable EPRI device is suitable for multimodal imaging, which can be used to study tumor redox status and therapeutic efficacy in cancer, and for combined analysis with other imaging modalities.
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Affiliation(s)
- Kazuhiro Kato
- Laboratory of Radiation Biology, Department of Applied Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Department of Applied Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan; One Health Research Center, Hokkaido University, Hokkaido, Japan.
| | - Hideo Sato-Akaba
- Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Miho C Emoto
- Department of Clinical Laboratory Science, School of Medical Technology, Health Sciences University of Hokkaido, Sapporo, Hokkaido, Japan
| | - Hirotada G Fujii
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Ishikari, Hokkaido, Japan
| | - Maciej M Kmiec
- Departments of Radiology and Radiation Oncology, Geisel School of Medicine, Dartmouth College, NH, USA
| | - Periannan Kuppusamy
- Departments of Radiology and Radiation Oncology, Geisel School of Medicine, Dartmouth College, NH, USA
| | - Yuki Mizuno
- Central Institute of Isotope Science, Hokkaido University, Sapporo, Hokkaido, Japan; Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Yuji Kuge
- Central Institute of Isotope Science, Hokkaido University, Sapporo, Hokkaido, Japan; Global Center for Biomedical Science and Engineering, Faculty of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Masaki Nagane
- Laboratory of Biochemistry, School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | - Tadashi Yamashita
- Laboratory of Biochemistry, School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | - Osamu Inanami
- Laboratory of Radiation Biology, Department of Applied Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan
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Voinov MA, Nunn N, Rana R, Davidsson A, Smirnov AI, Smirnova TI. Measuring local pH at interfaces from molecular tumbling: A concept for designing EPR-active pH-sensitive labels and probes. Org Biomol Chem 2024; 22:3652-3667. [PMID: 38647161 DOI: 10.1039/d4ob00167b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Molecular probes and indicators are broadly employed for pH measurements in bulk media and at interfaces. The underlying physical principle of pH measurements of most of these probes is based on a change in the electronic structure that, for example, results in a shift of the emission peak of the fluorescence probes, changes in NMR chemical shifts due to the affected electronic shielding, or magnetic parameters of pH-sensitive nitroxides as measured by EPR. Here we explore another concept for measuring local protonation state of molecular tags based on changes in rotational dynamics of electron spin-bearing moieties that are readily detected by conventional continuous wave X-band EPR. Such changes are especially pronounced at biological interfaces, such as lipid bilayer membranes, due to the probe interactions with adjacent charges and polarizable dipoles. The concept was demonstrated by synthesizing a series of pH-sensitive nitroxides and spin-labelled phospholipids. EPR spectra of these newly synthesized nitroxides exhibit relatively small - about 0.5 G - changes in isotropic nitrogen hyperfine coupling constant upon reversible protonation. However, spin-labelled phospholipids incorporated into lipid bilayers demonstrated almost 6-fold change in rotational correlation time upon protonation, readily allowing for pKa determination from large changes in EPR spectra. The demonstrated concept of EPR-based pH measurements leads to a broader range of potential nitroxide structures that can serve as molecular pH sensors at the desired pH range and, thus, facilitates further development of spin-labelling EPR methods to study electrostatic phenomena at chemical and biological interfaces.
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Affiliation(s)
- Maxim A Voinov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Nicholas Nunn
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Roshan Rana
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Atli Davidsson
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
| | - Tatyana I Smirnova
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695, USA.
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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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Usatov MS, Dobrynin SA, Polienko YF, Morozov DA, Glazachev YI, An’kov SV, Tolstikova TG, Gatilov YV, Bagryanskaya IY, Raizvikh AE, Bagryanskaya EG, Kirilyuk IA. Hydrophilic Reduction-Resistant Spin Labels of Pyrrolidine and Pyrroline Series from 3,4-Bis-hydroxymethyl-2,2,5,5-tetraethylpyrrolidine-1-oxyl. Int J Mol Sci 2024; 25:1550. [PMID: 38338825 PMCID: PMC10855552 DOI: 10.3390/ijms25031550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/18/2023] [Accepted: 12/24/2023] [Indexed: 02/12/2024] Open
Abstract
Highly resistant to reduction nitroxides open new opportunities for structural studies of biological macromolecules in their native environment inside living cells and for functional imaging of pH and thiols, enzymatic activity and redox status in living animals. 3,4-Disubstituted nitroxides of 2,2,5,5-tetraethylpyrrolidine and pyrroline series with a functional group for binding to biomolecules and a polar moiety for higher solubility in water and for more rigid attachment via additional coordination to polar sites were designed and synthesized. The EPR spectra, lipophilicities, kinetics of the reduction in ascorbate-containing systems and the decay rates in liver homogenates were measured. The EPR spectra of all 3,4-disubstituted pyrrolidine nitroxides showed additional large splitting on methylene hydrogens of the ethyl groups, while the spectra of similar pyrroline nitroxides were represented with a simple triplet with narrow lines and hyperfine structure of the nitrogen manifolds resolved in oxygen-free conditions. Both pyrrolidine and pyrroline nitroxides demonstrated low rates of reduction with ascorbate, pyrrolidines being a bit more stable than similar pyrrolines. The decay of positively charged nitroxides in the rat liver homogenate was faster than that of neutral and negatively charged radicals, with lipophilicity, rate of reduction with ascorbate and the ring type playing minor role. The EPR spectra of N,N-dimethyl-3,4-bis-(aminomethyl)-2,2,5,5-tetraethylpyrrolidine-1-oxyl showed dependence on pH with pKa = 3, ΔaN = 0.055 mT and ΔaH = 0.075 mT.
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Affiliation(s)
- Mikhail S. Usatov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
- Department of Natural Sciences, Novosibirsk State University, Pirogova Str. 1, Novosibirsk 630090, Russia
| | - Sergey A. Dobrynin
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Yuliya F. Polienko
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Denis A. Morozov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Yurii I. Glazachev
- Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya 3, Novosibirsk 630090, Russia;
| | - Sergey V. An’kov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Tatiana G. Tolstikova
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Yuri V. Gatilov
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Irina Yu. Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Arthur E. Raizvikh
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
- Department of Physics, Novosibirsk State University, Pirogova Str. 1, Novosibirsk 630090, Russia
| | - Elena G. Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
| | - Igor A. Kirilyuk
- N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, Novosibirsk 630090, Russia; (M.S.U.); (S.A.D.); (Y.F.P.); (D.A.M.); (S.V.A.); (T.G.T.); (Y.V.G.); (I.Y.B.); (A.E.R.); (E.G.B.)
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7
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Boussâa M, Abergel R, Durand S, Frapart YM. Ultrafast multiple paramagnetic species EPR imaging using a total variation based model. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 357:107583. [PMID: 37989061 DOI: 10.1016/j.jmr.2023.107583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/28/2023] [Accepted: 10/30/2023] [Indexed: 11/23/2023]
Abstract
An EPR spectrum or an EPR sinogram for imaging contains information about all the paramagnetic species that are in the analyzed sample. When only one species is present, an image of its spatial repartition can be reconstructed from the sinogram by using the well-known Filtered Back-Projection (FBP). However, in the case of several species, the FBP does not allow the reconstruction of the images of each species from a standard acquisition. One has to use for this spectral-spatial imaging whose acquisition can be very long. A new approach, based on Total Variation minimization, is proposed in order to efficiently extract the spatial repartitions of all the species present in a sample from standard imaging data and therefore drastically reduce the acquisition time. Experiments have been carried out on Tetrathiatriarylmethyl, nitroxide and DPPH.
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Affiliation(s)
- Mehdi Boussâa
- Université Paris Cité, CNRS, MAP5, F-75006 Paris, France; Université Paris Cité, CNRS, LCBPT, F-75006 Paris, France
| | - Rémy Abergel
- Université Paris Cité, CNRS, MAP5, F-75006 Paris, France
| | - Sylvain Durand
- Université Paris Cité, CNRS, MAP5, F-75006 Paris, France
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