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Maxouri O, Bodalal Z, Daal M, Rostami S, Rodriguez I, Akkari L, Srinivas M, Bernards R, Beets-Tan R. How to 19F MRI: applications, technique, and getting started. BJR Open 2023; 5:20230019. [PMID: 37953866 PMCID: PMC10636348 DOI: 10.1259/bjro.20230019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/26/2023] [Accepted: 08/01/2023] [Indexed: 11/14/2023] Open
Abstract
Magnetic resonance imaging (MRI) plays a significant role in the routine imaging workflow, providing both anatomical and functional information. 19F MRI is an evolving imaging modality where instead of 1H, 19F nuclei are excited. As the signal from endogenous 19F in the body is negligible, exogenous 19F signals obtained by 19F radiofrequency coils are exceptionally specific. Highly fluorinated agents targeting particular biological processes (i.e., the presence of immune cells) have been visualised using 19F MRI, highlighting its potential for non-invasive and longitudinal molecular imaging. This article aims to provide both a broad overview of the various applications of 19F MRI, with cancer imaging as a focus, as well as a practical guide to 19F imaging. We will discuss the essential elements of a 19F system and address common pitfalls during acquisition. Last but not least, we will highlight future perspectives that will enhance the role of this modality. While not an exhaustive exploration of all 19F literature, we endeavour to encapsulate the broad themes of the field and introduce the world of 19F molecular imaging to newcomers. 19F MRI bridges several domains, imaging, physics, chemistry, and biology, necessitating multidisciplinary teams to be able to harness this technology effectively. As further technical developments allow for greater sensitivity, we envision that 19F MRI can help unlock insight into biological processes non-invasively and longitudinally.
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Affiliation(s)
| | | | | | | | | | - Leila Akkari
- Division of Tumor Biology and Immunology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | | | - René Bernards
- Division of Molecular Carcinogenesis, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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Pavlova OS, Gulyaev MV, Gervits LL, Hurshkainen AA, Nikulin AV, Puchnin VM, Teploukhova ED, Kuropatkina TA, Anisimov NV, Medvedeva NA, Pirogov YA. Т 1 mapping of rat lungs in 19 F MRI using octafluorocyclobutane. Magn Reson Med 2023; 89:2318-2331. [PMID: 36744719 DOI: 10.1002/mrm.29606] [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: 05/24/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 02/07/2023]
Abstract
PURPOSE To demonstrate the feasibility of using octafluorocyclobutane (OFCB, c-C4 F8 ) for T1 mapping of lungs in 19 F MRI. METHODS The study was performed at 7 T in three healthy rats and three rats with pulmonary hypertension. To increase the sensitivity of 19 F MRI, a bent-shaped RF coil with periodic metal strips structure was used. The double flip angle method was used to calculate normalized transmitting RF field (B1n + ) maps and for correcting T1 maps built with the variable flip angle (VFA) method. The ultrashort TE pulse sequence was applied for acquiring MR images throughout the study. RESULTS The dependencies of OFCB relaxation times on its partial pressure in mixtures with oxygen, air, helium, and argon were obtained. T1 of OFCB linearly depended on its partial pressure with the slope of about 0.35 ms/kPa in the case of free diffusion. RF field inhomogeneity leads to distortion of T1 maps built with the VFA method, and therefore to high standard deviation of T1 in these maps. To improve the accuracy of the T1 maps, the B1n + maps were applied for VFA correction. This contributed to a 2-3-fold decrease in the SD of T1 values in the corresponding maps compared with T1 maps calculated without the correction. Three-dimensional T1 maps were obtained, and the mean T1 in healthy rat lungs was 35 ± 10 ms, and in rat lungs with pulmonary hypertension - 41 ± 9 ms. CONCLUSION OFCB has a spin-rotational relaxation mechanism and can be used for 19 F T1 mapping of lungs. The calculated OFCB maps captured ventilation defects induced by edema.
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Affiliation(s)
- Olga S Pavlova
- Faculty of Medicine, Lomonosov Moscow State University, Moscow, Russia.,Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia
| | - Mikhail V Gulyaev
- Faculty of Medicine, Lomonosov Moscow State University, Moscow, Russia
| | - Lev L Gervits
- Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Moscow, Russia
| | - Anna A Hurshkainen
- School of Physics and Engineering, ITMO University, St. Petersburg, Russia
| | - Anton V Nikulin
- Center of Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Viktor M Puchnin
- School of Physics and Engineering, ITMO University, St. Petersburg, Russia
| | | | | | | | | | - Yury A Pirogov
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia
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Sembhi R, Ranota T, Fox M, Couch M, Li T, Ball I, Ouriadov A. Feasibility of Dynamic Inhaled Gas MRI-Based Measurements Using Acceleration Combined with the Stretched Exponential Model. Diagnostics (Basel) 2023; 13:diagnostics13030506. [PMID: 36766611 PMCID: PMC9914115 DOI: 10.3390/diagnostics13030506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/22/2023] [Accepted: 01/28/2023] [Indexed: 02/01/2023] Open
Abstract
Dynamic inhaled gas (3He/129Xe/19F) MRI permits the acquisition of regional fractional-ventilation which is useful for detecting gas-trapping in lung-diseases such as lung fibrosis and COPD. Deninger's approach used for analyzing the wash-out data can be substituted with the stretched-exponential-model (SEM) because signal-intensity is attenuated as a function of wash-out-breath in 19F lung imaging. Thirteen normal-rats were studied using 3He/129Xe and 19F MRI and the ventilation measurements were performed using two 3T clinical-scanners. Two Cartesian-sampling-schemes (Fast-Gradient-Recalled-Echo/X-Centric) were used to test the proposed method. The fully sampled dynamic wash-out images were retrospectively under-sampled (acceleration-factors (AF) of 10/14) using a varying-sampling-pattern in the wash-out direction. Mean fractional-ventilation maps using Deninger's and SEM-based approaches were generated. The mean fractional-ventilation-values generated for the fully sampled k-space case using the Deninger method were not significantly different from other fractional-ventilation-values generated for the non-accelerated/accelerated data using both Deninger and SEM methods (p > 0.05 for all cases/gases). We demonstrated the feasibility of the SEM-based approach using retrospective under-sampling, mimicking AF = 10/14 in a small-animal-cohort from the previously reported dynamic-lung studies. A pixel-by-pixel comparison of the Deninger-derived and SEM-derived fractional-ventilation-estimates obtained for AF = 10/14 (≤16% difference) has confirmed that even at AF = 14, the accuracy of the estimates is high enough to consider this method for prospective measurements.
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Affiliation(s)
- Ramanpreet Sembhi
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Tuneesh Ranota
- Faculty of Engineering, School of Biomedical Engineering, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Matthew Fox
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Lawson Health Research Institute, London, ON N6C 2R5, Canada
| | - Marcus Couch
- Siemens Healthcare Limited, Montreal, QC H4R 2N9, Canada
| | - Tao Li
- Department of Chemistry, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
| | - Iain Ball
- Philips Australia and New Zealand, Sydney 2113, Australia
| | - Alexei Ouriadov
- Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
- Faculty of Engineering, School of Biomedical Engineering, The University of Western Ontario, London, ON N6A 3K7, Canada
- Lawson Health Research Institute, London, ON N6C 2R5, Canada
- Correspondence:
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4
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Bodalal Z, Katz S, Shi H, Beets-Tan R. "Advances in cancer imaging and technology"-special collection -introductory Editorial. BJR Open 2022; 4:20229003. [PMID: 38525165 PMCID: PMC10959000 DOI: 10.1259/bjro.20229003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
| | - Sharyn Katz
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
| | - Haibin Shi
- Center for Molecular Imaging and Nuclear Medicine, School of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou, China
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Trepakova AI, Skovpin IV, Chukanov NV, Salnikov OG, Chekmenev EY, Pravdivtsev AN, Hövener JB, Koptyug IV. Subsecond Three-Dimensional Nitrogen-15 Magnetic Resonance Imaging Facilitated by Parahydrogen-Based Hyperpolarization. J Phys Chem Lett 2022; 13:10253-10260. [PMID: 36301252 PMCID: PMC9983028 DOI: 10.1021/acs.jpclett.2c02705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Magnetic resonance imaging (MRI) provides unique information about the internal structure and function of living organisms in a non-invasive way. The use of conventional proton MRI for the observation of real-time metabolism is hampered by the dominant signals of water and fat, which are abundant in living organisms. Heteronuclear MRI in conjunction with the hyperpolarization methods does not encounter this issue. In this work, we polarized 15N nuclei of [15N1]fampridine (a drug used for the treatment of multiple sclerosis) to the level of 4% in nuclear magnetic resonance (NMR) experiments and 0.7% in MRI studies using spin-lock-induced crossing combined with signal amplification by reversible exchange. Consequently, three-dimensional 15N MRI of the hyperpolarized 15N-labeled drug was acquired in 0.1 s with a signal-to-noise ratio of 70. In addition, the NMR signal enhancements for 15N-enriched fampridine and fampridine with a natural abundance of 15N nuclei were compared and an explanation for their difference was proposed.
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Affiliation(s)
- Alexandra I. Trepakova
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
- Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090, Russia
- Institute of Cytology and Genetics, SB RAS, 10 Acad. Lavrentiev Ave., Novosibirsk, 630090, Russia
| | - Ivan V. Skovpin
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
| | - Nikita V. Chukanov
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
- Novosibirsk State University, 2 Pirogova St., Novosibirsk, 630090, Russia
| | - Oleg G. Salnikov
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
| | - Eduard Y. Chekmenev
- Department of Chemistry, Integrative Biosciences (Ibio), Karmanos Cancer Institute (KCI), Wayne State University, Detroit, Michigan, 48202, USA
- Russian Academy of Sciences (RAS), 14 Leninskiy Prospekt, Moscow, 119991, Russia
| | - Andrey N. Pravdivtsev
- Department of Radiology and Neuroradiology Section Biomedical Imaging, MOIN CC, Universitätsklinikum Schleswig-Holstein, Universität Kiel, 14 Am Botanischen Garten, Kiel, 24118, Germany
| | - Jan-Bernd Hövener
- Department of Radiology and Neuroradiology Section Biomedical Imaging, MOIN CC, Universitätsklinikum Schleswig-Holstein, Universität Kiel, 14 Am Botanischen Garten, Kiel, 24118, Germany
| | - Igor V. Koptyug
- International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
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Zhu H, Yin X, Zhou Y, Xu S, James TD, Wang L. Nanoplatforms with synergistic redox cycles and rich defects for activatable image-guided tumor-specific therapy. Chem 2022. [DOI: 10.1016/j.chempr.2022.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Sex-Dependent Protective Effect of Combined Application of Solubilized Ubiquinol and Selenium on Monocrotaline-Induced Pulmonary Hypertension in Wistar Rats. Antioxidants (Basel) 2022; 11:antiox11030549. [PMID: 35326199 PMCID: PMC8944686 DOI: 10.3390/antiox11030549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 12/19/2022] Open
Abstract
Ubiquinol exhibits anti-inflammatory and antioxidant properties. Selenium is a part of a number of antioxidant enzymes. The monocrotaline inducible model of pulmonary hypertension used in this study includes pathological links that may act as an application for the use of ubiquinol with high bioavailability and selenium metabolic products. On day 1, male and female rats were subcutaneously injected with a water-alcohol solution of monocrotaline or only water-alcohol solution. On days 7 and 14, some animals were intravenously injected with either ubiquinol’s vehicle or solubilized ubiquinol, or orally with selenium powder daily, starting from day 7, or received both ubiquinol + selenium. Magnetic resonance imaging of the lungs was performed on day 20. Hemodynamic parameters and morphometry were measured on day 22. An increased right ventricle systolic pressure in relation to control was demonstrated in all groups of animals of both sexes, except the group of males receiving the combination of ubiquinol + selenium. The relative mass of the right ventricle did not differ from the control in all groups of males and females receiving either ubiquinol alone or the combination. Magnetic resonance imaging revealed impaired perfusion in almost all animals examined, but pulmonary fibrosis developed in only half of the animals in the ubiquinol group. Intravenous administration of ubiquinol has a protective effect on monocrotaline-induced pulmonary hypertension development resulting in reduced right ventricle hypertrophy, and lung mass. Ubiquinol + selenium administration resulted in a less severe increase in the right ventricle systolic pressure in male rats but not in females 3 weeks after the start of the experiment. This sex-dependent effect was not observed in the influence of ubiquinol alone.
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Parsa J, O'Reilly T, Webb A. Very low field 19F MRI of perfluoro-octylbromide: Minimizing chemical shift effects and signal loss due to scalar coupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 325:106946. [PMID: 33676267 DOI: 10.1016/j.jmr.2021.106946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 06/12/2023]
Abstract
19F images have been obtained from perflurooctylbromide (PFOB) at very low magnetic field (50 mT). The small spectral dispersion (in Hz) means that all fluorine nuclei contribute to the signal without chemical shift artifacts or the need for specialized imaging sequences. Turbo spin echo trains with short interpulse intervals and full 180° refocussing pulses suppress scalar coupling, leading to long apparent T2 values and highly efficient data collection. Overall, the detection efficiency of PFOB is very similar that of water in tissue.
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Affiliation(s)
- Javad Parsa
- C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Department of Radiology, Albinusdreef 22333 ZA Leiden, the Netherlands
| | - Thomas O'Reilly
- C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Department of Radiology, Albinusdreef 22333 ZA Leiden, the Netherlands
| | - Andrew Webb
- C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Department of Radiology, Albinusdreef 22333 ZA Leiden, the Netherlands.
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Pirogov YA. Multinuclear MRI Research. APPLIED MAGNETIC RESONANCE 2021; 52:1695-1705. [PMID: 34366572 PMCID: PMC8325537 DOI: 10.1007/s00723-021-01401-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 05/14/2023]
Abstract
The presented data clearly demonstrate that multinuclear MRI has a great potential in research and clinical fields. The biomedical value of many heavy nuclei that are part of drugs, contrast agents, and molecular complexes in live tissues emphasizes the need for creating and using MRI scanners tuned to the Larmor frequencies of such nuclei. This article discusses a number of specific problems solved with the use of multinuclear MRI. Since the sensitivity of the MRI on heavy nuclei, as a rule, is insufficient for obtaining images of satisfactory quality, it is proposed to use hyperpolarization techniques for preparing objects for the MRI diagnostics. However, bearing in mind the high cost of hyperpolarization techniques, alternative approaches using contrast agents normally absent in tissues can be more suitable in certain situations. For instance, due to the absence of fluorine in the body, 19F MRI allows for successful diagnostics of the respiratory tract and lungs filled with fluorine-containing gas, detecting the location of the blood substitute Perftoran® in the body, monitoring the transport along the gastrointestinal tract of a capsule filled with a preparation containing fluorine-19 nuclei, etc. The possibility of non-invasive local measurements of the concentration of sodium-23 in the body, which, in case of a deviation from the norm, is linked to such pathologies as diabetes, hypertension, renal failure, and many others, is also demonstrated. Reported as well is the creation of transmitting and receiving infrastructure that makes possible effective MRI measurements at low fields (of about 0.5 T) at 10 Larmor frequencies corresponding to the nuclei of hydrogen, deuterium, fluorine, boron, chlorine, sodium, carbon, phosphorus, silicon and oxygen.
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Affiliation(s)
- Yu. A. Pirogov
- Faculty of Physics, M. V. Lomonosov Moscow State University, Moscow, Russia
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10
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Maunder A, Chan HF, Hughes PJC, Collier G, Norquay G, Rodgers O, Thelwall P, Robb F, Rao M, Wild JM. MR properties of 19 F C 3 F 8 gas in the lungs of healthy volunteers: T 2 ∗ and apparent diffusion coefficient at 1.5T and T 2 ∗ at 3T. Magn Reson Med 2020; 85:1561-1570. [PMID: 32926448 DOI: 10.1002/mrm.28511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/08/2020] [Accepted: 08/17/2020] [Indexed: 01/07/2023]
Abstract
PURPOSE To measure the transverse relaxation time ( T 2 ∗ ) and apparent diffusion coefficient (ADC) of 19 F-C3 F8 gas in vivo in human lungs at 1.5T and 3T, and to determine the representative distribution of values of these parameters in a cohort of healthy volunteers. METHODS Mapping of ADC at lung inflation levels of functional residual capacity (FRC) and total lung capacity (TLC) was performed with inhaled 19 F-C3 F8 (eight subjects) and 129 Xe (six subjects) at 1.5T. T 2 ∗ mapping with 19 F-C3 F8 was performed at 1.5T (at FRC and TLC) for 8 subjects and at 3T (at TLC for seven subjects). RESULTS At both FRC and TLC, the 19 F-C3 F8 ADC was smaller than the free diffusion coefficient demonstrating airway microstructural diffusion restriction. From FRC to TLC, the mean ADC significantly increased from 1.56 mm2 /s to 1.83 mm2 /s (P = .0017) for 19 F-C3 F8, and from 2.49 mm2 /s to 3.38 mm2 /s (P = .0015) for 129 Xe. The posterior-to-anterior gradient in ADC for FRC versus TLC in the superior half of the lungs was measured as 0.0308 mm2 /s per cm versus 0.0168 mm2 /s per cm for 19 F-C3 F8 and 0.0871 mm2 /s per cm versus 0.0326 mm2 /s per cm for 129 Xe. A consistent distribution of 19 F-C3 F8 T 2 ∗ values was observed in the lungs, with low values observed near the diaphragm and large pulmonary vessels. The mean T 2 ∗ across volunteers was 4.48 ms at FRC and 5.33 ms at TLC for 1.5T, and 3.78 ms at TLC for 3T. CONCLUSION In this feasibility study, values of physiologically relevant parameters of lung microstructure measurable by MRI ( T 2 ∗ , and ADC) were established for C3 F8 in vivo lung imaging in healthy volunteers.
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Affiliation(s)
- Adam Maunder
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Ho-Fung Chan
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Paul J C Hughes
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Guillhem Collier
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Graham Norquay
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Oliver Rodgers
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Peter Thelwall
- Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Fraser Robb
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom.,GE Healthcare, Aurora, Ohio, USA
| | - Madhwesha Rao
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
| | - Jim M Wild
- POLARIS, Imaging Group, Department of IICD, University of Sheffield, Sheffield, United Kingdom
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Shepelytskyi Y, Li T, Grynko V, Newman C, Hane FT, Albert MS. Evaluation of fluorine-19 magnetic resonance imaging of the lungs using octafluorocyclobutane in a rat model. Magn Reson Med 2020; 85:987-994. [PMID: 32789900 PMCID: PMC7689774 DOI: 10.1002/mrm.28473] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/13/2020] [Accepted: 07/21/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE To test octafluorocyclobutane (OFCB) as an inhalation contrast agent for fluorine-19 MRI of the lung, and to compare the image quality of OFCB scans with perfluoropropane (PFP) scans THEORY AND METHODS: After normalizing for the number of signal averages, a theoretical comparison between the OFCB signal-to-noise ratio (SNR) and PFP SNR predicted the average SNR advantage of 90% using OFCB during gradient echo imaging. The OFCB relaxometry was conducted using single-voxel spectroscopy and spin-echo imaging. A comparison of OFCB and PFP SNRs was performed in vitro and in vivo. Five healthy Sprague-Dawley rats were imaged during single breath-hold and continuous breathing using a Philips Achieva 3.0T MRI scanner (Philips, Andover, MA). The scan time was constant for both gases. Statistical comparison between PFP and OFCB scans was conducted using a paired t test and by calculating the Bayes factor. RESULTS Spin-lattice (T1 ) and effective spin-spin ( T 2 ∗ ) relaxation time constants of the pure OFCB gas were determined as 28.5 ± 1.2 ms and 10.5 ± 1.8 ms, respectively. Mixing with 21% of oxygen decreased T1 by 30% and T 2 ∗ by 20%. The OFCB in vivo images showed 73% higher normalized SNR on average compared with images acquired using PFP. The statistical significance was shown by both paired t test and calculated Bayes factors. The experimental results agree with theoretical calculations within the error of the relaxation parameter measurements. CONCLUSION The quality of the lung images acquired using OFCB was significantly better compared with PFP scans. The OFCB images had higher a SNR and were artifact-free.
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Affiliation(s)
- Yurii Shepelytskyi
- Chemistry and Materials Science Program, Lakehead University, Thunder Bay, Ontario, Canada.,Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada
| | - Tao Li
- Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada
| | - Vira Grynko
- Chemistry and Materials Science Program, Lakehead University, Thunder Bay, Ontario, Canada.,Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada
| | - Camryn Newman
- Biology Department, Lakehead University, Thunder Bay, Ontario, Canada
| | - Francis T Hane
- Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada.,Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada
| | - Mitchell S Albert
- Thunder Bay Regional Health Research Institute, Thunder Bay, Ontario, Canada.,Chemistry Department, Lakehead University, Thunder Bay, Ontario, Canada.,Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada
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