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Foongkajornkiat S, Sokolowski K, Stephenson J, Lloyd T, Hugo HJ, Thompson EW, Momot KI. Quantitative measurement of mammographic density in breast-tissue explants using portable NMR: Precision and accuracy. Magn Reson Med 2024; 92:374-388. [PMID: 38380719 DOI: 10.1002/mrm.30040] [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: 07/26/2023] [Revised: 12/20/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024]
Abstract
PURPOSE Single-sided portable NMR (pNMR) has previously been demonstrated to be suitable for quantification of mammographic density (MD) in excised breast tissue samples. Here we investigate the precision and accuracy of pNMR measurements of MD ex vivo as compared with the gold standards. METHODS Forty-five breast-tissue explants from 9 prophylactic mastectomy patients were measured. The relative tissue water content was taken as the MD-equivalent quantity. In each sample, the water content was measured using some combination of three pNMR techniques (apparent T2, diffusion, and T1 measurements) and two gold-standard techniques (computed microtomography [μCT] and hematoxylin and eosin [H&E] histology). Pairwise correlation plots and Bland-Altman analysis were used to quantify the degree of agreement between pNMR techniques and the gold standards. RESULTS Relative water content measured from both apparent T2 relaxation spectra, and diffusion decays exhibited strong correlation with the H&E and μCT results. Bland-Altman analysis yielded average bias values of -0.4, -2.6, 2.6, and 2.8 water percentage points (pp) and 95% confidence intervals of 13.1, 7.5, 11.2, and 11.8 pp for the H&E - T2, μCT - T2, H&E - diffusion, and μCT - diffusion comparison pairs, respectively. T1-based measurements were found to be less reliable, with the Bland-Altman confidence intervals of 27.7 and 33.0 pp when compared with H&E and μCT, respectively. CONCLUSION Apparent T2-based and diffusion-based pNMR measurements enable quantification of MD in breast-tissue explants with the precision of approximately 10 pp and accuracy of approximately 3 pp or better, making pNMR a promising measurement modality for radiation-free quantification of MD.
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Affiliation(s)
- Satcha Foongkajornkiat
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kamil Sokolowski
- Preclincal Imaging Facility, Translational Research Institute, Woolloongabba, Queensland, Australia
| | - James Stephenson
- Department of Breast and Endocrine Surgery, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
- Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Thomas Lloyd
- Department of Diagnostic Radiology, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
| | - Honor J Hugo
- School of Health and Behavioural Science, University of the Sunshine Coast, Sippy Downs, Queensland, Australia
- School of Medicine and Dentistry, Griffith University Sunshine Coast, Birtinya, Queensland, Australia
| | - Erik W Thompson
- Translational Research Institute, Woolloongabba, Queensland, Australia
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Konstantin I Momot
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland, Australia
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Kobayashi N. Optimization of flip angle and radiofrequency pulse phase to maximize steady-state magnetization in three-dimensional missing pulse steady-state free precession. NMR IN BIOMEDICINE 2024; 37:e5112. [PMID: 38299770 PMCID: PMC11078623 DOI: 10.1002/nbm.5112] [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: 07/18/2023] [Revised: 12/07/2023] [Accepted: 01/09/2024] [Indexed: 02/02/2024]
Abstract
Missing pulse (MP) steady-state free precession (SSFP) is a magnetic resonance imaging (MRI) pulse sequence that is highly tolerant to the magnetic field inhomogeneity. In this study, optimal flip angle and radiofrequency (RF) phase scheduling in three-dimensional (3D) MP-SSFP is introduced to maximize the steady-state magnetization while keeping broadband excitation to cover widely distributed frequencies generated by inhomogeneous magnetic fields. Numerical optimization based on extended phase graph (EPG) simulation was performed to maximize the MP-SSFP steady-state magnetization. To limit the specific absorption rate (SAR) associated with the broadband excitation in 3D MP-SSFP, SAR constraint was introduced in the numerical optimization. Optimized flip angle and RF phase settings were experimentally tested by introducing a linear inhomogeneous magnetic field in a range of 10-20 mT/m and using a phantom with known T1/T2 relaxation and diffusion parameters at 3 T. The experimental results were validated through comparisons with EPG simulation. Image contrasts and molecular diffusion effects were investigated in in vivo human brain imaging with 3D MP-SSFP with the optimal flip angle and RF phase settings. In the phantom measurements, the optimal flip angle and RF phase settings improved the MP-SSFP steady-state magnetization/signal-to-noise ratio by up to 41% under the fixed SAR conditions, which matched well with EPG simulation results. In vivo brain imaging with the optimal RF pulse settings provided T2-like image contrasts. Diffusion effects were relatively minor with the linear inhomogeneous field of 10-20 mT/m for white and gray matter, but cerebrospinal fluid showed conspicuous signal intensity attenuation as the linear inhomogeneous field increased. Numerical optimization achieved significant improvement in the steady-state magnetization in MP-SSFP compared with the RF pulse settings used in previous studies. The proposed flip angle and RF phase optimization is promising to improve 3D MP-SSFP image quality for MRI in inhomogeneous magnetic fields.
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Affiliation(s)
- Naoharu Kobayashi
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
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Capuani S, Maiuro A, Giampà E, Montuori M, Varrucciu V, Hagberg GE, Vinicola V, Colonna S. Assessment of Calcaneal Spongy Bone Magnetic Resonance Characteristics in Women: A Comparison between Measures Obtained at 0.3 T, 1.5 T, and 3.0 T. Diagnostics (Basel) 2024; 14:1050. [PMID: 38786348 PMCID: PMC11119204 DOI: 10.3390/diagnostics14101050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND There is a growing interest in bone tissue MRI and an even greater interest in using low-cost MR scanners. However, the characteristics of bone MRI remain to be fully defined, especially at low field strength. This study aimed to characterize the signal-to-noise ratio (SNR), T2, and T2* in spongy bone at 0.3 T, 1.5 T, and 3.0 T. Furthermore, relaxation times were characterized as a function of bone-marrow lipid/water ratio content and trabecular bone density. METHODS Thirty-two women in total underwent an MR-imaging investigation of the calcaneus at 0.3 T, 1.5 T, and 3.0 T. MR-spectroscopy was performed at 3.0 T to assess the fat/water ratio. SNR, T2, and T2* were quantified in distinct calcaneal regions (ST, TC, and CC). ANOVA and Pearson correlation statistics were used. RESULTS SNR increase depends on the magnetic field strength, acquisition sequence, and calcaneal location. T2* was different at 3.0 T and 1.5 T in ST, TC, and CC. Relaxation times decrease as much as the magnetic field strength increases. The significant linear correlation between relaxation times and fat/water found in healthy young is lost in osteoporotic subjects. CONCLUSION The results have implications for the possible use of relaxation vs. lipid/water marrow content for bone quality assessment and the development of quantitative MRI diagnostics at low field strength.
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Affiliation(s)
- Silvia Capuani
- CNR-ISC c/o Physics Department, “Sapienza” University of Rome, P.zle Aldo Moro 5, 00185 Rome, Italy; (A.M.); (M.M.)
- Neuroimaging Laboratory, Santa Lucia Foundation, IRCCS Rome, Via Ardeatina 309, 00179 Rome, Italy
| | - Alessandra Maiuro
- CNR-ISC c/o Physics Department, “Sapienza” University of Rome, P.zle Aldo Moro 5, 00185 Rome, Italy; (A.M.); (M.M.)
- Physics Department, “Sapienza” University of Rome, P.zle Aldo Moro 5, 00185 Rome, Italy
| | - Emiliano Giampà
- Rehabilitation Hospital, Santa Lucia Foundation, IRCCS Rome, Via Ardeatina 309, 00179 Rome, Italy; (E.G.); (V.V.)
| | - Marco Montuori
- CNR-ISC c/o Physics Department, “Sapienza” University of Rome, P.zle Aldo Moro 5, 00185 Rome, Italy; (A.M.); (M.M.)
| | - Viviana Varrucciu
- Radiology Department, Santa Lucia Foundation, IRCCS Rome, Via Ardeatina 309, 00179 Rome, Italy; (V.V.); (S.C.)
| | - Gisela E. Hagberg
- High Field Magnetic Resonance, Max-Planck-Institute for Biological Cybernetics, 72076 Tübingen, Germany;
| | - Vincenzo Vinicola
- Rehabilitation Hospital, Santa Lucia Foundation, IRCCS Rome, Via Ardeatina 309, 00179 Rome, Italy; (E.G.); (V.V.)
| | - Sergio Colonna
- Radiology Department, Santa Lucia Foundation, IRCCS Rome, Via Ardeatina 309, 00179 Rome, Italy; (V.V.); (S.C.)
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He J, Kong X, Xu Z. Improving the SNR of UMR sensor using LC resonator. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 356:107580. [PMID: 37924681 DOI: 10.1016/j.jmr.2023.107580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/06/2023]
Abstract
Single-sided or unilateral magnetic resonance (UMR) technology has various benefits, such as an open structure, low cost, portability, and nondestructive measurement, in contrast to the conventional closed magnet structure. UMR is widely used in material analysis, well logging, and biomedicine. However, its development is constrained by its poor signal-to-noise ratio (SNR). To enhance the SNR of UMR sensor, a surface coil of LC resonator is added on the Radio Frequency (RF) coil. First, a method of calculating the current in the RF coil including LC resonator is derived. Next, the equivalent AC resistance of the coil is calculated using the partial-element equivalent-circuit (PEEC) method. Finally, the SNR of a UMR sensor incorporating LC resonator is analyzed, and its sensitivity map is provided. Experimental comparisons are made between the UMR sensor with and without a LC resonator. Results show that the SNR of the UMR can be enhanced by up to three times after the LC resonator is loaded. The SNR improves within 30 mm of the coil surface, and this beneficial effect steadily diminishes as the distance increases. This study offers a useful method for improving the signal of UMR sensors.
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Affiliation(s)
- Jiali He
- School of Electrical Engineering, Chongqing University, Chongqing, China
| | - Xiaohan Kong
- Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814, Japan
| | - Zheng Xu
- School of Electrical Engineering, Chongqing University, Chongqing, China.
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Portable NMR for quantification of breast density in vivo: Proof-of-concept measurements and comparison with quantitative MRI. Magn Reson Imaging 2022; 92:212-223. [PMID: 35843446 DOI: 10.1016/j.mri.2022.07.004] [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: 03/22/2022] [Revised: 06/17/2022] [Accepted: 07/11/2022] [Indexed: 11/23/2022]
Abstract
Mammographic Density (MD) is the degree of radio-opacity of the breast in an X-ray mammogram. It is determined by the Fibroglandular: Adipose tissue ratio. MD has major implications in breast cancer risk and breast cancer chemoprevention. This study aimed to investigate the feasibility of accurate, low-cost quantification of MD in vivo without ionising radiation. We used single-sided portable nuclear magnetic resonance ("Portable NMR") due to its low cost and the absence of radiation-related safety concerns. Fifteen (N = 15) healthy female volunteers were selected for the study and underwent an imaging routine consisting of 2D X-ray mammography, quantitative breast 3T MRI (Dixon and T1-based 3D compositional breast imaging), and 1D compositional depth profiling of the right breast using Portable NMR. For each participant, all the measurements were made within 3-4 h of each other. MRI-determined tissue water content was used as the MD-equivalent quantity. Portable NMR depth profiles of tissue water were compared with the equivalent depth profiles reconstructed from Dixon and T1-based MR images, which were used as the MD-equivalent reference standard. The agreement between the depth profiles acquired using Portable NMR and the reconstructed reference-standard profiles was variable but overall encouraging. The agreement was somewhat inferior to that seen in breast tissue explant measurements conducted in vitro, where quantitative micro-CT was used as the reference standard. The lower agreement in vivo can be attributed to an uncertainty in the positioning of the Portable NMR sensor on the breast surface and breast compression in Portable NMR measurements. The degree of agreement between Portable NMR and quantitative MRI is encouraging. While the results call for further development of quantitative Portable NMR, they demonstrate the in-principle feasibility of Portable NMR-based quantitative compositional imaging in vivo and show promise for the development of safe and low-cost protocols for quantification of MD suitable for clinical applications.
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Kharbanda Y, Urbańczyk M, Zhivonitko VV, Mailhiot S, Kettunen MI, Telkki VV. Sensitive, Efficient and Portable Analysis of Molecular Exchange Processes by Hyperpolarized Ultrafast NMR. Angew Chem Int Ed Engl 2022; 61:e202203957. [PMID: 35499690 PMCID: PMC9400989 DOI: 10.1002/anie.202203957] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Indexed: 11/08/2022]
Abstract
Molecular exchange processes are ubiquitous in nature. Here, we introduce a method to analyze exchange processes by using low-cost, portable, single-sided NMR instruments. The inherent magnetic field inhomogeneity of the single-sided instruments is exploited to achieve diffusion contrast of exchange sites and spatial encoding of 2D data. This so-called ultrafast diffusion exchange spectroscopy method shortens the experiment time by two to four orders of magnitude. Furthermore, because full 2D data are measured in a single scan (in a fraction of a second), the sensitivity of the experiment can be improved by several orders of magnitude using so-called nuclear spin hyperpolarization methods (in this case, dissolution dynamic nuclear polarization). As the first demonstration of the feasibility of the method in various applications, we show that the method enables quantification of intra- and extracellular exchange of water in a yeast cell suspension.
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Affiliation(s)
| | - Mateusz Urbańczyk
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | | | - Sarah Mailhiot
- NMR Research Unit, University of Oulu, Oulu, 90540, Finland
| | - Mikko I Kettunen
- Kuopio Biomedical Imaging Unit, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
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7
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Kharbanda Y, Urbańczyk M, Zhivonitko VV, Mailhiot S, Kettunen MI, Telkki V. Sensitive, Efficient and Portable Analysis of Molecular Exchange Processes by Hyperpolarized Ultrafast NMR. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Mateusz Urbańczyk
- Institute of Physical Chemistry Polish Academy of Sciences Warsaw Poland
| | | | | | - Mikko I. Kettunen
- Kuopio Biomedical Imaging Unit A.I. Virtanen Institute for Molecular Sciences University of Eastern Finland Kuopio Finland
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NMR Profiling of Reaction and Transport in Thin Layers: A Review. Polymers (Basel) 2022; 14:polym14040798. [PMID: 35215714 PMCID: PMC8963059 DOI: 10.3390/polym14040798] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/25/2022] [Accepted: 02/14/2022] [Indexed: 02/04/2023] Open
Abstract
Reaction and transport processes in thin layers of between 10 and 1000 µm are important factors in determining their performance, stability and degradation. In this review, we discuss the potential of high-gradient Nuclear Magnetic Resonance (NMR) as a tool to study both reactions and transport in these layers spatially and temporally resolved. As the NMR resolution depends on gradient strength, the high spatial resolution required in submillimeter layers can only be achieved with specially designed high-gradient setups. Three different high-gradient setups exist: STRAFI (STRay FIeld), GARField (Gradient-At-Right-angles-to-Field) and MOUSE (MObile Universal Surface Explorer). The aim of this review is to provide a detailed overview of the three techniques and their ability to visualize reactions and transport processes using physical observable properties such as hydrogen density, diffusion, T1- and T2-relaxation. Finally, different examples from literature will be presented to illustrate the wide variety of applications that can be studied and the corresponding value of the techniques.
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Thomas DG, Galvosas P, Tzeng YC, Harrison FG, Berry MJ, Teal PD, Wright GA, Obruchkov S. Oxygen saturation-dependent effects on blood transverse relaxation at low fields. MAGMA (NEW YORK, N.Y.) 2022; 35:805-815. [PMID: 35107697 PMCID: PMC9463268 DOI: 10.1007/s10334-021-00993-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/28/2021] [Accepted: 12/15/2021] [Indexed: 11/28/2022]
Abstract
Objective Blood oxygenation can be measured using magnetic resonance using the paramagnetic effect of deoxy-haemoglobin, which decreases the \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 relaxation time of blood. This \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 contrast has been well characterised at the \documentclass[12pt]{minimal}
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\begin{document}$$\textit{B}_{{0}}$$\end{document}B0 fields used in MRI (1.5 T and above). However, few studies have characterised this effect at lower magnetic fields. Here, the feasibility of blood oximetry at low field based on \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 changes that are within a physiological relevant range is explored. This study could be used for specifying requirements for construction of a monitoring device based on low field permanent magnet systems. Methods A continuous flow circuit was used to control parameters such as oxygen saturation and temperature in a sample of blood. It flowed through a variable field magnet, where CPMG experiments were performed to measure its \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2. In addition, the oxygen saturation was monitored by an optical sensor for comparison with the \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 changes. Results These results show that at low \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 due to oxygenation is small, but still detectable. The data measured at low fields are also in agreement with theoretical models for the oxy-deoxy \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 effect. Conclusion \documentclass[12pt]{minimal}
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\begin{document}$$\textit{T}_{2}$$\end{document}T2 changes in blood due to oxygenation were observed at fields as low as 0.1 T. These results suggest that low field NMR relaxometry devices around 0.3 T could be designed to detect changes in blood oxygenation.
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Affiliation(s)
- Dion G Thomas
- School of Chemical and Physical Sciences and MacDiarmid Institute for Advanced Materials, Victoria University of Wellington, Wellington, New Zealand
| | - Petrik Galvosas
- School of Chemical and Physical Sciences and MacDiarmid Institute for Advanced Materials, Victoria University of Wellington, Wellington, New Zealand
| | - Yu-Chieh Tzeng
- Centre for Translational Research, University of Otago, Wellington, New Zealand
| | - Freya G Harrison
- Centre for Translational Research, University of Otago, Wellington, New Zealand
| | - Mary J Berry
- Centre for Translational Research and Department of Paediatrics and Child Health, University of Otago, Wellington, New Zealand
| | - Paul D Teal
- School of Engineering and Computer Science, Victoria University of Wellington, Wellington, New Zealand
| | - Graham A Wright
- Sunnybrook Research Institute and University of Toronto, Toronto, ON, Canada
| | - Sergei Obruchkov
- Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand.
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Ahmadi S, Aguilera AR, MacMillan B, Mastikhin I. Studies of periodic seawater spray icing with unilateral NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 334:107109. [PMID: 34844074 DOI: 10.1016/j.jmr.2021.107109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/29/2021] [Accepted: 11/15/2021] [Indexed: 06/13/2023]
Abstract
Sea water ice has a complicated pore structure consisting of brine-filled pockets within a solid ice matrix. In this work, an unilateral Nuclear Magnetic Resonance instrument was used to characterize the evolution of sea-ice brine inclusions in two types of ice: stationary seawater ice and seawater spray ice formed by periodic spraying on horizontal and vertical surfaces. The portable unilateral NMR was capable of measuring very low amounts of brine (<10% of the water-filled volume). CPMG experiments were performed to extract the information on brine content and T2 distribution at temperatures between -6 °C and -16 °C. 1D imaging was used to spatially resolve the ice brine accumulation. The results show that the seawater spray ice growth, brine content (greater for the horizontal orientation than for the vertical one), and T2 distribution (unimodal for stationary ice and bimodal for spray ice) depend on temperature and surface orientation.
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Affiliation(s)
- Shahla Ahmadi
- UNB MRI Centre, Department of Physics, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada
| | - Andrés Ramírez Aguilera
- UNB MRI Centre, Department of Physics, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada
| | - Bryce MacMillan
- UNB MRI Centre, Department of Physics, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada
| | - Igor Mastikhin
- UNB MRI Centre, Department of Physics, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
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11
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Utsuzawa S, Tang Y, Song YQ. Inside-out NMR with two concentric ring magnets. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 333:107082. [PMID: 34688178 DOI: 10.1016/j.jmr.2021.107082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
We report the design and the implementation of an inside-out NMR sensor that produces a large sensitive region with substantially uniform magnetic field at a remote location. The construction using a pair of ring magnets is simple yet provides multiple benefits, including large sample volume, operation with low RF power, and the ability to measure samples with long T2 and high diffusivity. A palm-size inside-out NMR sensor (57 mm OD × 29 mm height, 420 g including the housing and the coil PCB) was built with inexpensive magnets. The sweet spot is located ∼5 mm above the magnet surface with ∼4 mm width and ∼5 mm height assuming t180 = 18 μs. The field strength at that point is 0.16 T and achieved SNR ∼23 per two scans when operated with ∼10 W peak RF power. Its quasi-uniform B0 around the saddle point allows the measurement of T2 = 1.5 s with a 100 μs echo time.
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Affiliation(s)
- Shin Utsuzawa
- Schlumberger-Doll Research, Cambridge, MA 02139, USA.
| | - Yiqiao Tang
- Schlumberger-Doll Research, Cambridge, MA 02139, USA
| | - Yi-Qiao Song
- Schlumberger-Doll Research, Cambridge, MA 02139, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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12
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Wang Y, Xu Y, Zhang M, Emmanuel Komolafe T, Wang W, Luo H, Chen X, Yang X, Wu Z. A single-sided magnet for deep-depth fat quantification. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 331:107053. [PMID: 34428727 DOI: 10.1016/j.jmr.2021.107053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 06/06/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Early detection of fatty-liver disease is important before further aggravations of the disease, such as cirrhosis, can develop. In this study, we developed a low-cost, movable single-sided magnet for in vivo liver fat quantification. A gradient field of 73.5 G/cm and a field strength of 0.0725 T were obtained by structurally optimizing the concave U-shaped magnet, on which the region of interest (ROI) was a curved shape about 0.4 mm thick, 8 cm above the surface of the radiofrequency (RF) coil. We constructed a prototype nuclear magnetic-resonance (NMR) relaxometry system based on this optimized magnet. Subsequent phantom experiments demonstrated the effectiveness of the single-sided magnet in evaluating different proton density fat fraction (PDFF) phantoms. As expected, the results of the six phantoms showed good positive correlation between PDFF and the fitted fat amplitude, which suggested that single-sided NMR relaxometry could be used to quantify liver fat in vivo.
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Affiliation(s)
- Ya Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu, China; School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Yajie Xu
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu, China
| | - Mingkang Zhang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu, China; School of Electronic and Information Engineering, Changchun University of Science and Technology, 130022, Changchun, China
| | - Temitope Emmanuel Komolafe
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu, China; School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China
| | - Weiqian Wang
- Wuxi Marvel Stone Healthcare Co. Ltd., Wuxi 214135, Jiangsu, China
| | - Hai Luo
- Wuxi Marvel Stone Healthcare Co. Ltd., Wuxi 214135, Jiangsu, China
| | - Xiao Chen
- Wuxi Marvel Stone Healthcare Co. Ltd., Wuxi 214135, Jiangsu, China
| | - Xiaodong Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu, China.
| | - Ziyue Wu
- Wuxi Marvel Stone Healthcare Co. Ltd., Wuxi 214135, Jiangsu, China.
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13
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Silva P, Jouda M, Korvink J. Magnetostatic reciprocity for MR magnet design. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:607-617. [PMID: 37905211 PMCID: PMC10539805 DOI: 10.5194/mr-2-607-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 06/29/2021] [Indexed: 11/02/2023]
Abstract
Electromagnetic reciprocity has long been a staple in magnetic resonance (MR) radio-frequency development, offering geometrical insights and a figure of merit for various resonator designs. In a similar manner, we use magnetostatic reciprocity to compute manufacturable solutions of complex magnet geometries, by establishing a quantitative metric for the placement and subsequent orientation of discrete pieces of permanent magnetic material. Based on magnetostatic theory and non-linear finite element modelling (FEM) simulations, it is shown how assembled permanent magnet setups perform in the embodiment of a variety of designs and how magnetostatic reciprocity is leveraged in the presence of difficulties associated with self-interactions, to fulfil various design objectives, including self-assembled micro-magnets, adjustable magnetic arrays, and an unbounded magnetic field intensity in a small volume, despite realistic saturation field strengths.
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Affiliation(s)
- Pedro Freire Silva
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, 76131 Karlsruhe, Germany
| | - Mazin Jouda
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, 76131 Karlsruhe, Germany
| | - Jan G. Korvink
- Karlsruhe Institute of Technology (KIT), Institute of Microstructure Technology, 76131 Karlsruhe, Germany
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14
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Rudszuck T, Zick K, Groß D, Nirschl H, Guthausen G. Dedicated NMR sensor to analyze relaxation and diffusion in liquids and its application to characterize lubricants. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:825-834. [PMID: 33754398 DOI: 10.1002/mrc.5155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/10/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
A dedicated nuclear magnetic resonance (NMR) sensor was designed for the analysis of liquids. The magnets are arranged in a V shape, creating a spatially dependent magnetic field in the gap. Measurements of samples with diverse diameters are possible underdefined magnetic field gradients at a given position. The magnet thus combines properties of single sided NMR with high static magnetic field gradients and classical time domain (TD) devices with lower to almost zero gradients. The sensor can easily be adapted to the requirements of the considered investigation; probes can be customized. On the example of lubricants and their aging, the added value and applicability of this sensor in quality control are highlighted in this publication. Relaxation and diffusion were measured by Carr-Purcell-Meiboom-Gill (CPMG) while varying the echo time τe and quantified via numerical modeling. Especially, relaxation shows a high sensitivity towards aging of lubricants such as particulate abrasion and changes in molecular dynamics induced, for example, by additive depletion. The applicability of this NMR sensor in quality control is demonstrated on the example of engine and transmission oils as well as of lubrication greases.
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Affiliation(s)
- Thomas Rudszuck
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
| | - Klaus Zick
- Bruker BioSpin GmbH, Rheinstetten, Germany
| | | | - Hermann Nirschl
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
| | - Gisela Guthausen
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
- Engler-Bunte Institut, Water Science and Technology, KIT, Karlsruhe, Germany
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15
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Barbieri M, Fantazzini P, Testa C, Bortolotti V, Baruffaldi F, Kogan F, Brizi L. Characterization of Structural Bone Properties through Portable Single-Sided NMR Devices: State of the Art and Future Perspectives. Int J Mol Sci 2021; 22:7318. [PMID: 34298936 PMCID: PMC8303251 DOI: 10.3390/ijms22147318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 11/18/2022] Open
Abstract
Nuclear Magnetic Resonance (NMR) is a well-suited methodology to study bone composition and structural properties. This is because the NMR parameters, such as the T2 relaxation time, are sensitive to the chemical and physical environment of the 1H nuclei. Although magnetic resonance imaging (MRI) allows bone structure assessment in vivo, its cost limits the suitability of conventional MRI for routine bone screening. With difficulty accessing clinically suitable exams, the diagnosis of bone diseases, such as osteoporosis, and the associated fracture risk estimation is based on the assessment of bone mineral density (BMD), obtained by the dual-energy X-ray absorptiometry (DXA). However, integrating the information about the structure of the bone with the bone mineral density has been shown to improve fracture risk estimation related to osteoporosis. Portable NMR, based on low-field single-sided NMR devices, is a promising and appealing approach to assess NMR properties of biological tissues with the aim of medical applications. Since these scanners detect the signal from a sensitive volume external to the magnet, they can be used to perform NMR measurement without the need to fit a sample inside a bore of a magnet, allowing, in principle, in vivo application. Techniques based on NMR single-sided devices have the potential to provide a high impact on the clinical routine because of low purchasing and running costs and low maintenance of such scanners. In this review, the development of new methodologies to investigate structural properties of trabecular bone exploiting single-sided NMR devices is reviewed, and current limitations and future perspectives are discussed.
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Affiliation(s)
- Marco Barbieri
- Department of Radiology, Stanford University, Stanford, CA 94395, USA;
- Department of Physics and Astronomy “Augusto Righi”, University of Bologna, 40127 Bologna, Italy; (P.F.); (C.T.)
| | - Paola Fantazzini
- Department of Physics and Astronomy “Augusto Righi”, University of Bologna, 40127 Bologna, Italy; (P.F.); (C.T.)
| | - Claudia Testa
- Department of Physics and Astronomy “Augusto Righi”, University of Bologna, 40127 Bologna, Italy; (P.F.); (C.T.)
- IRCCS Istituto delle Scienze Neurologiche Bologna, Functional and Molecular Neuroimaging Unit, 40139 Bologna, Italy
| | - Villiam Bortolotti
- Department of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, 40134 Bologna, Italy;
| | - Fabio Baruffaldi
- Medical Technology Laboratory, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy;
| | - Feliks Kogan
- Department of Radiology, Stanford University, Stanford, CA 94395, USA;
| | - Leonardo Brizi
- Department of Physics and Astronomy “Augusto Righi”, University of Bologna, 40127 Bologna, Italy; (P.F.); (C.T.)
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16
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Blümich B, Anders J. When the MOUSE leaves the house. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:149-160. [PMID: 37904756 PMCID: PMC10539780 DOI: 10.5194/mr-2-149-2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/10/2021] [Indexed: 11/01/2023]
Abstract
Change is inherent to time being transient. With the NMR-MOUSE (MObile Universal Surface Explorer) having matured into an established NMR tool for nondestructive testing of materials, this forward-looking retrospective assesses the challenges the NMR-MOUSE faced when deployed outside a protected laboratory and how its performance quality can be maintained and improved when operated under adverse conditions in foreign environments. This work is dedicated to my dear colleague and friend Geoffrey Bodenhausen on the occasion of his crossing an honorable timeline in appreciation of his ever-continuing success of fueling the dynamics of magnetic resonance.
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Affiliation(s)
- Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen
University, 52159 Roetgen, Germany
| | - Jens Anders
- Institute of Smart Sensors, University of Stuttgart, 70569 Stuttgart, Germany
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17
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Barbieri M, Fantazzini P, Bortolotti V, Baruffaldi F, Festa A, Manners DN, Testa C, Brizi L. Single-sided NMR to estimate morphological parameters of the trabecular bone structure. Magn Reson Med 2020; 85:3353-3369. [PMID: 33349979 DOI: 10.1002/mrm.28648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 11/06/2022]
Abstract
PURPOSE Single-sided 1 H-NMR is proposed for the estimation of morphological parameters of trabecular bone, and potentially the detection of pathophysiological alterations of bone structure. In this study, a new methodology was used to estimate such parameters without using an external reference signal, and to study intratrabecular and intertrabecular porosities, with a view to eventually scanning patients. METHODS Animal trabecular bone samples were analyzed by a single-sided device. The Carr-Purcell-Meiboom-Gill sequence of 1 H nuclei of fluids, including marrow, confined inside the bone, was analyzed by quasi-continuous T2 distributions and separated into two 1 H pools: short and long T2 components. The NMR parameters were estimated using models of trabecular bone structure, and compared with the corresponding micro-CT. RESULTS Without any further assumptions, the internal reference parameter (short T2 signal intensity fraction) enabled prediction of the micro-CT parameters BV/TV (volume of the trabeculae/total sample volume) and BS/TV (external surface of the trabeculae/total sample volume) with linear correlation coefficient >0.80. The assignment of the two pools to intratrabecular and intertrabecular components yielded an estimate of average intratrabecular porosity (33 ± 5)%. Using the proposed models, the NMR-estimated BV/TV and BS/TV were found to be linearly related to the corresponding micro-CT values with high correlation (>0.90 for BV/TV; >0.80 for BS/TV) and agreement coefficients. CONCLUSION Low-field, low-cost portable devices that rely on intrinsic magnetic field gradients and do not use ionizing radiation are viable tools for in vitro preclinical studies of pathophysiological structural alterations of trabecular bone.
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Affiliation(s)
- Marco Barbieri
- Physics and Astronomy Department, University of Bologna, Bologna, Italy.,Department of Radiology, Stanford University, Stanford, CA, USA
| | - Paola Fantazzini
- Physics and Astronomy Department, University of Bologna, Bologna, Italy
| | - Villiam Bortolotti
- Department of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, Bologna, Italy
| | | | - Anna Festa
- IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - David N Manners
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Claudia Testa
- Physics and Astronomy Department, University of Bologna, Bologna, Italy.,National Institute for Nuclear Physics Bologna, Bologna, Italy
| | - Leonardo Brizi
- Physics and Astronomy Department, University of Bologna, Bologna, Italy.,National Institute for Nuclear Physics Bologna, Bologna, Italy
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18
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Kobayashi N, Parkinson B, Idiyatullin D, Adriany G, Theilenberg S, Juchem C, Garwood M. Development and validation of 3D MP-SSFP to enable MRI in inhomogeneous magnetic fields. Magn Reson Med 2020; 85:831-844. [PMID: 32892400 DOI: 10.1002/mrm.28469] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/19/2020] [Accepted: 07/16/2020] [Indexed: 01/27/2023]
Abstract
PURPOSE We demonstrate the feasibility of MRI with missing-pulse steady-state free precession (MP-SSFP) in a 4T magnet with artificially degraded homogeneity. METHODS T1 , T2 , and diffusion contrast of MP-SSFP was simulated with constant and alternate radiofrequency (RF) phase using an extended phase graph. To validate MP-SSFP performance in human brain imaging, MP-SSFP was tested with two types of artificially introduced inhomogeneous magnetic fields: (1) a pure linear gradient field, and (2) a pseudo-linear gradient field introduced by mounting a head-gradient set at 36 cm from the magnet isocenter. Image distortion induced by the nonlinear inhomogeneous field was corrected using B0 mapping measured with MP-SSFP. RESULTS The maximum flip angle in MP-SSFP was limited to ≤10° because of the large range of resonance frequencies in the inhomogeneous magnetic fields tested in this study. Under this flip-angle limitation, MP-SSFP with constant RF phase provided advantages of higher signal-to-noise ratio and insensitivity to B1 + field inhomogeneity as compared with an alternate RF phase. In diffusion simulation, the steady-state magnetization in constant RF phase MP-SSFP increased with an increase of static field gradient up to 8 to 21 mT/m depending on simulation parameters. Experimental results at 4T validated these findings. In human brain imaging, MP-SSFP preserved sufficient signal intensities, but images showed severe image distortion from the pseudo-linear inhomogeneous field. However, following distortion correction, good-quality brain images were achieved. CONCLUSION MP-SSFP appears to be a feasible MRI technique for brain imaging in an inhomogeneous magnetic field.
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Affiliation(s)
- Naoharu Kobayashi
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ben Parkinson
- Robinson Research Institute, Victoria University of Wellington, Wellington, New Zealand
| | - Djaudat Idiyatullin
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gregor Adriany
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Christoph Juchem
- Department of Biomedical Engineering, Columbia University, New York, New York, USA.,Department of Radiology, Columbia University, New York, New York, USA
| | - Michael Garwood
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
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19
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Wald LL, McDaniel PC, Witzel T, Stockmann JP, Cooley CZ. Low-cost and portable MRI. J Magn Reson Imaging 2020; 52:686-696. [PMID: 31605435 PMCID: PMC10644353 DOI: 10.1002/jmri.26942] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/04/2019] [Indexed: 11/16/2023] Open
Abstract
Research in MRI technology has traditionally expanded diagnostic benefit by developing acquisition techniques and instrumentation to enable MRI scanners to "see more." This typically focuses on improving MRI's sensitivity and spatiotemporal resolution, or expanding its range of biological contrasts and targets. In complement to the clear benefits achieved in this direction, extending the reach of MRI by reducing its cost, siting, and operational burdens also directly benefits healthcare by increasing the number of patients with access to MRI examinations and tilting its cost-benefit equation to allow more frequent and varied use. The introduction of low-cost, and/or truly portable scanners, could also enable new point-of-care and monitoring applications not feasible for today's scanners in centralized settings. While cost and accessibility have always been considered, we have seen tremendous advances in the speed and spatial-temporal capabilities of general-purpose MRI scanners and quantum leaps in patient comfort (such as magnet length and bore diameter), but only modest success in the reduction of cost and siting constraints. The introduction of specialty scanners (eg, extremity, brain-only, or breast-only scanners) have not been commercially successful enough to tilt the balance away from the prevailing model: a general-purpose scanner in a centralized healthcare location. Portable MRI scanners equivalent to their counterparts in ultrasound or even computed tomography have not emerged and MR monitoring devices exist only in research laboratories. Nonetheless, recent advances in hardware and computational technology as well as burgeoning markets for MRI in the developing world has created a resurgence of interest in the topic of low-cost and accessible MRI. This review examines the technical forces and trade-offs that might facilitate a large step forward in the push to "jail-break" MRI from its centralized location in healthcare and allow it to reach larger patient populations and achieve new uses. Level of Evidence: 5 Technical Efficacy Stage: 6 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2020;52:686-696.
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Affiliation(s)
- Lawrence L. Wald
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
- Division of Health Sciences and Technology, Harvard – Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Patrick C. McDaniel
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Thomas Witzel
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Jason P. Stockmann
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Clarissa Zimmerman Cooley
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
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20
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Taugeron P, Bricaud S, Kehlet C, Dittmer J. Profiles of paint layer samples obtained in the fringe field of a high field magnet by means of very short broadband frequency-modulated pulses. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:870-879. [PMID: 32384575 DOI: 10.1002/mrc.5038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 03/24/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
In this article, we describe the acquisition of depth profiles, in particular of paint layers, in the static gradient of a high field magnet, providing a superior sensitivity. The main objective are reference profiles that help to understand scans made with noninvasive unilateral nuclear magnetic resonance (NMR), which often suffers from poor signal-to-noise ratio when working with real samples. Various technical aspects like the coil geometry and the limit of resolution are investigated. A major advancement is the use of frequency-modulated pulses that are very broadband and at the same time very short (25 μs). The latter is necessary to allow the acquisition of a CPMG echo train of old, rigid paint material. Despite being far from adiabatic, they provide uniform excitation and refocusing over 1 MHz, which corresponds to about 400 μm with the used gradient. We show that the uniformity is even sufficient to obtain biexponential relaxation profiles. With these tools, a paint sample from a restoration campaign is analyzed with different contrast criteria: The original and two layers from former restoration attempts can be visualized, and furthermore, the relaxation profiles allow to study the migration of plasticizing molecules.
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Affiliation(s)
- Pierre Taugeron
- Institut des Molécules et Matériaux du Mans (IMMM), UMR 6283 CNRS - Le Mans Université, Le Mans, France
| | - Sullivan Bricaud
- Institut des Molécules et Matériaux du Mans (IMMM), UMR 6283 CNRS - Le Mans Université, Le Mans, France
| | - Cindie Kehlet
- Department of Mathematics and Science, Pratt Institute, Brooklyn, NY, USA
| | - Jens Dittmer
- Institut des Molécules et Matériaux du Mans (IMMM), UMR 6283 CNRS - Le Mans Université, Le Mans, France
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21
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Blümich B. Low-field and benchtop NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 306:27-35. [PMID: 31311709 DOI: 10.1016/j.jmr.2019.07.030] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/03/2019] [Accepted: 07/08/2019] [Indexed: 05/28/2023]
Abstract
NMR started at low field. Important discoveries like the first observation of NMR in condensed matter, the spin echo, NMR for chemical analysis, Fourier NMR spectroscopy, 2D NMR spectroscopy and magnetic resonance imaging happened at field strengths considered low today. With time the footprint of the NMR instruments at these field strengths shrunk from the laboratory floor to the tabletop. The first commercial tabletop NMR instruments were compact relaxometers for food analysis followed by mobile relaxometers for materials testing and oil-well exploration culminating in tabletop spectrometers for chemical analysis, capable of performing nearly the whole methodical portfolio of today's high-field instruments. The increasing sensitivity afforded by the lower noise of modern electronics and the unfolding richness of hyperpolarization scenarios along with detection schemes alternative to nuclear induction enable NMR at ultra-low field strengths down to zero applied field, where spin-spin couplings in local fields dominate the residual Zeeman interaction. Miniaturization and cost-reduction of NMR instruments outline current development goals along with the development of smart-phone-like apps to conduct standard NMR analyses.
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Affiliation(s)
- Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany.
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22
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Keschenau PR, Simons N, Klingel H, Reuter S, Foldenauer AC, Vieß J, Weidener D, Andruszkow J, Blümich B, Tolba R, Jacobs MJ, Kalder J. Perfusion-related changes in intestinal diffusion detected by NMR-MOUSE® monitoring in minipigs. Microvasc Res 2019; 125:103876. [DOI: 10.1016/j.mvr.2019.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 04/22/2019] [Accepted: 04/28/2019] [Indexed: 02/07/2023]
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23
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McDaniel PC, Cooley CZ, Stockmann JP, Wald LL. The MR Cap: A single-sided MRI system designed for potential point-of-care limited field-of-view brain imaging. Magn Reson Med 2019; 82:1946-1960. [PMID: 31231885 DOI: 10.1002/mrm.27861] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/06/2019] [Accepted: 05/23/2019] [Indexed: 01/08/2023]
Abstract
PURPOSE The size, cost, and siting requirements of conventional MRI systems limit their availability and preclude usage as monitoring or point-of-care devices. To address this, we developed a lightweight MRI for point-of-care brain imaging over a reduced field of view (FOV). METHODS The B0 magnet was designed with a genetic algorithm optimizing homogeneity over a 3 × 8 × 8 cm FOV and a built-in gradient for slice selection or readout encoding. An external pair of gradient coils enables phase encoding in the other two directions and a radiofrequency (RF) coil provides excitation and detection. The system was demonstrated with high-resolution 1D "depth profiling" and 3D phantom imaging. RESULTS The lightweight B0 magnet achieved a 64-mT average field over the imaging region at a materials cost of <$450 USD. The weight of the magnet, gradient, and RF coil was 8.3 kg. Depth profiles were obtained at high resolution (0.89 mm) and multislice rapid acquisition with refocused echoes (RARE) images were obtained with a resolution ~2 mm in-plane and ~6-mm slice thickness, each in an imaging time of 11 min. CONCLUSION The system demonstrates the feasibility of a lightweight brain MRI system capable of 1D to 3D imaging within a reduced FOV. The proposed system is low-cost and small enough to be used in point-of-care applications.
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Affiliation(s)
- Patrick C McDaniel
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts.,Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Clarissa Zimmerman Cooley
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | - Jason P Stockmann
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | - Lawrence L Wald
- Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts.,Harvard Medical School, Boston, Massachusetts.,Division of Health Sciences and Technology, Harvard-Massachusetts Institute of Technology, Cambridge, Massachusetts
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24
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Huang X, Ali TS, Nano T, Blick T, Tse BWC, Sokolowski K, Tourell MC, Lloyd T, Thompson EW, Momot KI, Hugo HJ. Quantification of breast tissue density: Correlation between single-sided portable NMR and micro-CT measurements. Magn Reson Imaging 2019; 62:111-120. [PMID: 31176808 DOI: 10.1016/j.mri.2019.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/23/2019] [Accepted: 06/06/2019] [Indexed: 01/21/2023]
Abstract
Mammographic density (MD) is a strong independent risk factor for breast cancer. Traditional screening for MD using X-ray mammography involves ionising radiation, which is not suitable for young women, those with previous radiation exposure, or those having undergone a partial mastectomy. Therefore, alternative approaches for MD screening that do not involve ionising radiation will be important as the clinical use of MD increases, and as more frequent MD testing becomes desirable for research purposes. We have previously demonstrated the potential utility of spin relaxation-based, single-sided portable-NMR measurements for the purpose of MD quantification. We present here a more refined analysis by quantifying breast tissue density in excised samples on a continuous scale (0% to 100% fibroglandular tissue content) using micro-CT (μCT), and comparing the results to spin-relaxation and diffusion portable-NMR measurements of the same samples. μCT analysis of mammary tissues containing high- and low-MD (HMD and LMD, respectively) regions had Hounsfield Unit (HU) histograms with a bimodal pattern, with HMD regions exhibiting significantly higher HU values than LMD regions. Quantitative MD (%HMD) values obtained using μCT exhibited an excellent correlation with portable-NMR results, namely longitudinal spin-relaxation time constants (T1) and the relative tissue water content obtained from portable-NMR diffusion measurements (R2 = 0.92, p < 0.0001 and R2 = 0.96, p < 0.0001, respectively). These findings are consistent with our previous results demonstrating relatively high water content in HMD breast tissue, consistent with the high proportion of fibroglandular tissue, FGT, which in turn contains more abundant water-carrying HSPG proteins. We observed an excellent correlation between the T1 values and diffusion NMR-measured relative tissue water content (R2 = 0.94, p < 0.0001). These findings demonstrate, for the first time, the ability of single-sided portable NMR to accurately quantify MD in vitro on a continuous scale. The results also indicate that portable-NMR analysis can assist in the identification of features underpinning MD, namely FGT and adipose tissue content. Future work will involve application of portable NMR to quantifying MD in vivo.
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Affiliation(s)
- Xuan Huang
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; Translational Research Institute, Woolloongabba, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia
| | - Tonima S Ali
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia
| | - Teresa Nano
- Greenslopes Private Hospital, Greenslopes, Australia
| | - Tony Blick
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; Translational Research Institute, Woolloongabba, Australia
| | - Brian Wan-Chi Tse
- Preclincal Imaging Facility, Translational Research Institute, Woolloongabba, Australia
| | - Kamil Sokolowski
- Preclincal Imaging Facility, Translational Research Institute, Woolloongabba, Australia
| | - Monique C Tourell
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia
| | - Thomas Lloyd
- Radiology Department, Princess Alexandra Hospital, Woolloongabba, Australia
| | - Erik W Thompson
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; Translational Research Institute, Woolloongabba, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia; University of Melbourne, Department of Surgery, St. Vincent's Hospital, Melbourne, Australia
| | - Konstantin I Momot
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia
| | - Honor J Hugo
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia; Translational Research Institute, Woolloongabba, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia.
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25
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Ali TS, Tourell MC, Hugo HJ, Pyke C, Yang S, Lloyd T, Thompson EW, Momot KI. Transverse relaxation-based assessment of mammographic density and breast tissue composition by single-sided portable NMR. Magn Reson Med 2019; 82:1199-1213. [PMID: 31034648 DOI: 10.1002/mrm.27781] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE Elevated mammographic density (MD) is an independent risk factor for breast cancer (BC) as well as a source of masking in X-ray mammography. High-frequency longitudinal monitoring of MD could also be beneficial in hormonal BC prevention, where early MD changes herald the treatment's success. We present a novel approach to quantification of MD in breast tissue using single-sided portable NMR. Its development was motivated by the low cost of portable-NMR instrumentation, the suitability for measurements in vivo, and the absence of ionizing radiation. METHODS Five breast slices were obtained from three patients undergoing prophylactic mastectomy or breast reduction surgery. Carr-Purcell-Meiboom-Gill (CPMG) relaxation curves were measured from (1) regions of high and low MD (HMD and LMD, respectively) in the full breast slices; (2) the same regions excised from the full slices; and (3) excised samples after H2 O-D2 O replacement. T2 distributions were reconstructed from the CPMG decays using inverse Laplace transform. RESULTS Two major peaks, identified as fat and water, were consistently observed in the T2 distributions of HMD regions. The LMD T2 distributions were dominated by the fat peak. The relative areas of the two peaks exhibited statistically significant (P < .005) differences between HMD and LMD regions, enabling their classification as HMD or LMD. The relative-area distributions exhibited no statistically significant differences between full slices and excised samples. CONCLUSION T2 -based portable-NMR analysis is a novel approach to MD quantification. The ability to quantify tissue composition, combined with the low cost of instrumentation, make this approach promising for clinical applications.
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Affiliation(s)
- Tonima S Ali
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
| | - Monique C Tourell
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
| | - Honor J Hugo
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.,School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia.,Translational Research Institute, Woolloongabba, Australia
| | - Chris Pyke
- Department of Surgery, Mater Hospital, University of Queensland, St Lucia, Australia
| | - Samuel Yang
- Department of Plastic and Reconstructive Surgery, Greenslopes Private Hospital, Brisbane, Australia
| | - Thomas Lloyd
- Division of Radiology, Princess Alexandra Hospital, Woolloongabba, Australia
| | - Erik W Thompson
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.,School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia.,Translational Research Institute, Woolloongabba, Australia.,University of Melbourne Department of Surgery, St Vincent's Hospital, Melbourne, Australia
| | - Konstantin I Momot
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
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Keschenau PR, Klingel H, Reuter S, Foldenauer AC, Vieß J, Weidener D, Andruszkow J, Bluemich B, Tolba R, Jacobs MJ, Kalder J. Evaluation of the NMR-MOUSE as a new method for continuous functional monitoring of the small intestine during different perfusion states in a porcine model. PLoS One 2018; 13:e0206697. [PMID: 30388139 PMCID: PMC6214547 DOI: 10.1371/journal.pone.0206697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/17/2018] [Indexed: 12/31/2022] Open
Abstract
Objective The study aim was to evaluate a small low-field NMR (nuclear magnetic resonance) scanner, the NMR-MOUSE®, for detecting changes in intestinal diffusion under different (patho-) physiological perfusion states. Methods Laparotomy was performed on 8 female landrace pigs (body weight 70±6 kg) and the feeding vessels of several intestinal loops were dissected. Successively, the intestinal loops were examined using O2C (oxygen to see, LEA Medizintechnik GmbH, Giessen, Germany) for microcirculatory monitoring and the NMR-MOUSE® for diffusion measurement (fast and slow components). On each loop the baseline measurement (physiological perfusion) was followed by one of the following main procedures: method 1 –ischemia; method 2 –flow reduction; method 3 –intraluminal glucose followed by ischemia; method 4 –intraluminal glucose followed by flow reduction. Additionally, standard perioperative monitoring (blood pressure, ECG, blood gas analyses) and histological assessment of intestinal biopsies was performed. Results There was no statistical overall time and method effect in the NMR-MOUSE measurement (fast component: ptime = 0.6368, pmethod = 0.9766, slow component: ptime = 0.8216, pmethod = 0.7863). Yet, the fast component of the NMR-MOUSE measurement showed contrary trends during ischemia (increase) versus flow reduction (decrease). The slow-to-fast diffusion ratio shifted slightly towards slow diffusion during flow reduction. The O2C measurement showed a significant decrease of oxygen saturation and microcirculatory blood flow during ischemia and flow reduction (p < .0001). The local microcirculatory blood amount (rHb) showed a significant mucosal increase (pClamping(method 1) = 0.0007, pClamping(method 3) = 0.0119), but a serosal decrease (pClamping(method 1) = 0.0119, pClamping(method 3) = 0.0078) during ischemia. The histopathological damage was significantly higher with increasing experimental duration and at the end of methods 3 and 4 (p < .0001,Fisher-test). Conclusion Monitoring intestinal diffusion changes due to different perfusion states using the NMR-MOUSE is feasible under experimental conditions. Despite the lack of statistical significance, this technique reflects perfusion changes and therefore seems promising for the evaluation of different intestinal perfusion states in the future. Beforehand however, an optimization of this technology, including the optimization of the penetration depth, as well as further validation studies under physiological conditions and including older animals are required.
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Affiliation(s)
- Paula R. Keschenau
- Department of Vascular Surgery, European Vascular Center Aachen-Maastricht, RWTH University Hospital Aachen, Aachen, Germany
| | - Hanna Klingel
- Department of Vascular Surgery, European Vascular Center Aachen-Maastricht, RWTH University Hospital Aachen, Aachen, Germany
| | - Silke Reuter
- Institut für Technische und Makromolekulare Chemie, RWTH University Aachen, Aachen, Germany
| | | | - Jochen Vieß
- Institut für Technische und Makromolekulare Chemie, RWTH University Aachen, Aachen, Germany
| | - Dennis Weidener
- Institut für Technische und Makromolekulare Chemie, RWTH University Aachen, Aachen, Germany
| | - Julia Andruszkow
- Institute for Pathology, RWTH University Hospital Aachen, Aachen, Germany
| | - Bernhard Bluemich
- Institut für Technische und Makromolekulare Chemie, RWTH University Aachen, Aachen, Germany
| | - René Tolba
- Institute for Laboratory Animal Science and Experimental Surgery, RWTH University Aachen, Aachen, Germany
| | - Michael J. Jacobs
- Department of Vascular Surgery, European Vascular Center Aachen-Maastricht, RWTH University Hospital Aachen, Aachen, Germany
- Department of Vascular Surgery, European Vascular Center Aachen-Maastricht, AZM University Hospital Maastricht, Maastricht, The Netherlands
| | - Johannes Kalder
- Department of Vascular Surgery, European Vascular Center Aachen-Maastricht, RWTH University Hospital Aachen, Aachen, Germany
- * E-mail:
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Überrück T, Rehorn C, Höhner R, Blümich B. Visualizing the detection area of a unilateral NMR sensor using deconvolution and back-projection. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 296:169-175. [PMID: 30286412 DOI: 10.1016/j.jmr.2018.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/18/2018] [Accepted: 09/19/2018] [Indexed: 06/08/2023]
Abstract
Understanding the detection volume of a unilateral NMR sensor is crucial to interpret acquired data appropriately. Whereas this is easily done in the sensor's axial dimension by running a depth profile on a well-defined sample, the lateral dimension is commonly characterized with very small samples, where each position along a regular grid is scanned individually, typically resulting in measurement times of several days and a resolution that is limited to the dimensions of the sample. Here we apply two mathematical procedures known from image processing that employ samples larger than the pixel size to characterize the lateral detection area. One procedure uses deconvolution algorithms to account for blurring effects caused by a larger sample while the other utilizes back-projection of radial field profiles. Both approaches are demonstrated with a Profile NMR-MOUSE® (PM5). They yield field maps in good agreement with those acquired with pixel-size test samples but save about one order of magnitude in scanning time.
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Affiliation(s)
- Till Überrück
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany
| | - Christian Rehorn
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany
| | - Robin Höhner
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany
| | - Bernhard Blümich
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie, Worringerweg 2, 52074 Aachen, Germany
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28
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Mohebbi B, Tavangarrad AH, Claussen J, Blümich B, Hassanizadeh SM, Rosati R. Revealing how interfaces in stacked thin fibrous layers affect liquid ingress and transport properties by single-sided NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 294:16-23. [PMID: 29966854 DOI: 10.1016/j.jmr.2018.06.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 06/22/2018] [Accepted: 06/23/2018] [Indexed: 06/08/2023]
Abstract
Offering multifaceted applications, thin fibrous porous materials are mostly used in stacks of layers, each layer having a defined functionality. Since only a few pores exist across a layer a couple of hundred microns thick, the interface between layers may significantly affect liquid ingress. Thus, the main objective of the study is to substantiate that an interface layer is present during liquid infiltration between stacked thin fibrous layers and that it affects the fluid transport properties. A compact single-sided NMR device with a low static gradient of about 2 T/m perpendicular to the sensor surface and a uniform magnetic field in lateral directions was used to profile a 2-mm thick slice in one shot. The liquid ingress into the thin fibrous layers and their interfaces was visualized by Fourier-transforming the NMR signal and processing the time-dependent 1D profiles with a newly developed mathematical method. The flow characteristics and liquid distribution profiles of a 400-µm thick layer were compared with those of two stacked 200-µm thick layers from the same material but with an interface between them. The results show major differences in distributions and flow dynamics for the single and dual layer cases, which reveal the importance of the interface in fluid flow.
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Affiliation(s)
- Behzad Mohebbi
- Institute for Technical and Macromolecular Chemistry, Worringerweg 2, RWTH Aachen University, 52056 Aachen, Germany; Procter&Gamble Service GmbH, Sulzbacher Str. 40, 65824 Schwalbach am Taunus, Germany.
| | - Amir Hossein Tavangarrad
- Department of Earth Sciences, Environmental Hydrogeology Group, Utrecht University, Princetonplein 9, 3584CC Utrecht, The Netherlands
| | - Jan Claussen
- Procter&Gamble Service GmbH, Sulzbacher Str. 40, 65824 Schwalbach am Taunus, Germany
| | - Bernhard Blümich
- Institute for Technical and Macromolecular Chemistry, Worringerweg 2, RWTH Aachen University, 52056 Aachen, Germany
| | - S Majid Hassanizadeh
- Department of Earth Sciences, Environmental Hydrogeology Group, Utrecht University, Princetonplein 9, 3584CC Utrecht, The Netherlands
| | - Rodrigo Rosati
- Procter&Gamble Service GmbH, Sulzbacher Str. 40, 65824 Schwalbach am Taunus, Germany
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29
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Bashyam A, Li M, Cima MJ. Design and experimental validation of Unilateral Linear Halbach magnet arrays for single-sided magnetic resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 292:36-43. [PMID: 29763794 DOI: 10.1016/j.jmr.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
Single-sided NMR has the potential for broad utility and has found applications in healthcare, materials analysis, food quality assurance, and the oil and gas industry. These sensors require a remote, strong, uniform magnetic field to perform high sensitivity measurements. We demonstrate a new permanent magnet geometry, the Unilateral Linear Halbach, that combines design principles from "sweet-spot" and linear Halbach magnets to achieve this goal through more efficient use of magnetic flux. We perform sensitivity analysis using numerical simulations to produce a framework for Unilateral Linear Halbach design and assess tradeoffs between design parameters. Additionally, the use of hundreds of small, discrete magnets within the assembly allows for a tunable design, improved robustness to variability in magnetization strength, and increased safety during construction. Experimental validation using a prototype magnet shows close agreement with the simulated magnetic field. The Unilateral Linear Halbach magnet increases the sensitivity, portability, and versatility of single-sided NMR.
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Affiliation(s)
- Ashvin Bashyam
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States; Electrical Engineering & Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States.
| | - Matthew Li
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States; Harvard-MIT Program of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States.
| | - Michael J Cima
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States; Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, United States.
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30
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Blümich B, Rehorn C, Zia W. Magnets for Small-Scale and Portable NMR. MICRO AND NANO SCALE NMR 2018. [DOI: 10.1002/9783527697281.ch1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Bernhard Blümich
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie; Worringerweg 2 52074 Aachen Germany
| | - Christian Rehorn
- RWTH Aachen University, Institut für Technische und Makromolekulare Chemie; Worringerweg 2 52074 Aachen Germany
| | - Wasif Zia
- Sir Peter Mansfield Imaging Center, University of Nottingham; United Kingdom
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31
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Rehorn C, Blümich B. Unilaterale NMR zur Untersuchung von Kunst und Kulturgut. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201713009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Christian Rehorn
- Institut für Technische und Makromolekulare Chemie; RWTH Aachen University; Aachen Deutschland
| | - Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie; RWTH Aachen University; Aachen Deutschland
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32
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Rehorn C, Blümich B. Cultural Heritage Studies with Mobile NMR. Angew Chem Int Ed Engl 2018; 57:7304-7312. [PMID: 29600567 DOI: 10.1002/anie.201713009] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/13/2018] [Indexed: 11/12/2022]
Abstract
Nuclear magnetic resonance (NMR) provides in situ information about selected isotope densities in samples and objects, while also providing contrast through rotational and translational molecular dynamics. These parameters are probed not only in NMR spectroscopy and imaging but also in nondestructive materials testing by mobile stray-field NMR, the unique properties of which are valuable in cultural heritage studies. We present recent progress in the analysis of cultural heritage with mobile 1 H NMR stray-field sensors, for which the detection zone is outside of the NMR magnet. Prominent applications include the analysis of stratigraphies in paintings and frescoes, and the assessment of material states changing under the impact of aging, conservation, and restoration.
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Affiliation(s)
- Christian Rehorn
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany
| | - Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany
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33
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Tourell MC, Ali TS, Hugo HJ, Pyke C, Yang S, Lloyd T, Thompson EW, Momot KI. T 1 -based sensing of mammographic density using single-sided portable NMR. Magn Reson Med 2018; 80:1243-1251. [PMID: 29399874 DOI: 10.1002/mrm.27098] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 12/16/2017] [Accepted: 12/31/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Monique C Tourell
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
| | - Tonima S Ali
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
| | - Honor J Hugo
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.,School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia.,Translational Research Institute, Woolloongabba, Australia
| | - Chris Pyke
- Department of Surgery, Mater Hospital, University of Queensland, St Lucia, Australia
| | - Samuel Yang
- Department of Plastic and Reconstructive Surgery, Greenslopes Private Hospital, Brisbane, Australia
| | - Thomas Lloyd
- Division of Radiology, Princess Alexandra Hospital, Woolloongabba, Australia
| | - Erik W Thompson
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.,School of Biomedical Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia.,Translational Research Institute, Woolloongabba, Australia.,University of Melbourne Department of Surgery, St Vincent's Hospital, Melbourne, Australia
| | - Konstantin I Momot
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
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34
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Blümich B, Singh K. Desktop NMR and Its Applications From Materials Science To Organic Chemistry. Angew Chem Int Ed Engl 2017; 57:6996-7010. [PMID: 29230908 DOI: 10.1002/anie.201707084] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 12/19/2022]
Abstract
NMR spectroscopy is an indispensable method of analysis in chemistry, which until recently suffered from high demands for space, high costs for acquisition and maintenance, and operational complexity. This has changed with the introduction of compact NMR spectrometers suitable for small-molecule analysis on the chemical workbench. These spectrometers contain permanent magnets giving rise to proton NMR frequencies between 40 and 80 MHz. The enabling technology is to make small permanent magnets with homogeneous fields. Tabletop instruments with inhomogeneous fields have been in use for over 40 years for characterizing food and hydrogen-containing materials by relaxation and diffusion measurements. Related NMR instruments measure these parameters in the stray field outside the magnet. They are used to inspect the borehole walls of oil wells and to test objects nondestructively. The state-of-the-art of NMR spectroscopy, imaging and relaxometry with compact instruments is reviewed.
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Affiliation(s)
- Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany
| | - Kawarpal Singh
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany
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35
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Blümich B, Singh K. NMR mit Tischgeräten und deren Anwendungen von der Materialwissenschaft bis zur organischen Chemie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie; RWTH Aachen University; Aachen Deutschland
| | - Kawarpal Singh
- Institut für Technische und Makromolekulare Chemie; RWTH Aachen University; Aachen Deutschland
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36
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Wang Q, Gao R, Liu S. Topology optimization based design of unilateral NMR for generating a remote homogeneous field. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 279:51-59. [PMID: 28463746 DOI: 10.1016/j.jmr.2017.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 04/07/2017] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
This paper presents a topology optimization based design method for the design of unilateral nuclear magnetic resonance (NMR), with which a remote homogeneous field can be obtained. The topology optimization is actualized by seeking out the optimal layout of ferromagnetic materials within a given design domain. The design objective is defined as generating a sensitive magnetic field with optimal homogeneity and maximal field strength within a required region of interest (ROI). The sensitivity of the objective function with respect to the design variables is derived and the method for solving the optimization problem is presented. A design example is provided to illustrate the utility of the design method, specifically the ability to improve the quality of the magnetic field over the required ROI by determining the optimal structural topology for the ferromagnetic poles. Both in simulations and experiments, the sensitive region of the magnetic field achieves about 2 times larger than that of the reference design, validating validates the feasibility of the design method.
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Affiliation(s)
- Qi Wang
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
| | - Renjing Gao
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China
| | - Shutian Liu
- State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China.
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Judeinstein P, Ferdeghini F, Oliveira-Silva R, Zanotti JM, Sakellariou D. Low-field single-sided NMR for one-shot 1D-mapping: Application to membranes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 277:25-29. [PMID: 28213048 DOI: 10.1016/j.jmr.2017.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/02/2017] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
Many single-sided permanent magnet NMR systems have been proposed over the years allowing for 1D proton-density profiling, diffusion measurements and relaxometry. In this manuscript we make use of a recently published unilateral magnet for low-field NMR exhibiting an extremely uniform magnetic field gradient with moderate strength and cylindrical symmetry, allowing for a well-defined sweet spot. Combined with a goniometer, our system is used to characterize precisely the uniformity of its gradient and to achieve micrometric precision 1D profiling, as well as spatially localized relaxometry and diffusometry on thick (∼150μm) membrane samples. Profiling with this magnet did not require repositioning of the samples with respect to the 1D tomograph.
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Affiliation(s)
- Patrick Judeinstein
- Laboratoire Léon Brillouin, CNRS-CEA (UMR 12), CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France; Laboratoire de Physique des Solides, (UMR CNRS 8502), Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Filippo Ferdeghini
- Laboratoire Léon Brillouin, CNRS-CEA (UMR 12), CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Rodrigo Oliveira-Silva
- Laboratoire Léon Brillouin, CNRS-CEA (UMR 12), CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Jean-Marc Zanotti
- Laboratoire Léon Brillouin, CNRS-CEA (UMR 12), CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Dimitrios Sakellariou
- NIMBE, CEA-CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
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The Novel Design of a Single-Sided MRI Probe for Assessing Burn Depth. SENSORS 2017; 17:s17030526. [PMID: 28272320 PMCID: PMC5375812 DOI: 10.3390/s17030526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/03/2017] [Indexed: 01/03/2023]
Abstract
Burn depth assessment in clinics is still inaccurate because of the lack of feasible and practical testing devices and methods. Therefore, this process often depends on subjective judgment of burn surgeons. In this study, a new unilateral magnetic resonance imaging (UMRI) sensor equipped with a 2D gradient coil system was established, and we attempted to assess burns using unilateral nuclear magnetic resonance devices. A reduced Halbach magnet was utilized to generate a magnetic field that was relatively homogeneous on a target plane with a suitable field of view for 2D spatial localization. A uniplanar gradient coil system was designed by utilizing the mainstream target field method, and a uniplanar RF (radio frequency) coil was designed by using a time-harmonic inverse method for the UMRI sensor. A 2D image of the cross sections of a simple burn model was obtained by a fast 2D pure-phase encoding imaging method. The design details of the novel single-sided MRI probe and imaging tests are also presented.
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39
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Blümich B. Virtual special issue: Magnetic resonance at low fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 274:145-147. [PMID: 27742163 DOI: 10.1016/j.jmr.2016.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Monitoring of Cellular Changes in the Bone Marrow following PTH(1-34) Treatment of OVX Rats Using a Portable Stray-Field NMR Scanner. J Osteoporos 2017; 2017:7910432. [PMID: 28638673 PMCID: PMC5468560 DOI: 10.1155/2017/7910432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Osteoporosis is characterized by reduction in trabecular bone in conjunction with increased marrow cell adiposity. While these changes occur within weeks, monitoring of treatment efficacy as performed by DEXA is sensitive only to long-term changes. MRI is sensitive to bone marrow changes but is less affordable. In a recent study, we have shown that a stray-field NMR can monitor bone marrow cellular changes that are related to osteoporosis. Objectives. To demonstrate sensitivity of a low-field tabletop NMR scanner to bone marrow dynamics following hormonal treatment in rats. Methods. Two-month-old female rats (n = 36) were ovariectomized (OVX) and dosed for the ensuing 3 or 5 weeks with 20 mg/kg of PTH(1-34). Hind limbs femurs and tibiae were isolated and underwent ex vivo microradiography and histology and NMR relaxometry at 6 weeks (preventive experiment) and 11 weeks (therapeutic treatment experiment) after OVX. Results. OVX rats developed osteoporotic changes including adipogenic marrow compared to Sham and PTH treated rats. T2 and ADC NMR relaxation coefficients were found to correlate with marrow composition. Conclusions. This study suggests that stray-field NMR, an affordable method that is sensitive to the rapid cellular changes in bone marrow, may have a clinical value in monitoring hormonal treatment for osteoporosis.
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Sarda Y, Bergman E, Hillel I, Binderman I, Nevo U. Detection of bone marrow changes related to estrogen withdrawal in rats with a tabletop stray-field NMR scanner. Magn Reson Med 2016; 78:860-870. [PMID: 27690262 DOI: 10.1002/mrm.26472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 08/22/2016] [Accepted: 08/27/2016] [Indexed: 11/06/2022]
Abstract
PURPOSE Osteoporosis is characterized by a decrease in bone mineral density (BMD). A preliminary stage of the disease is progressive bone marrow adiposity, caused by imbalance between osteogenesis and adipogenesis in the marrow. Detection of osteoporosis relies on the quantification of BMD with techniques such as dual-energy X-ray absorptiometry. This work aimed to detect bone marrow changes in an experimental model of osteopenia using a low-field tabletop NMR scanner. METHODS An experiment was performed on 32 female rats, 3 months old, 16 of which were ovariectomized (OVX) and 16 were sham-operated (sham). The femur and tibia from both hind limbs were isolated and underwent ex vivo NMR scans at four time points after the OVX and sham operations. NMR scans were complemented by BMD measurements and histology. RESULTS Significant changes in the bone marrow of ovariectomized rats, relative to sham operated rats, were observed after 3.5 and 4.5 months. Bone marrow adiposity was detected by significant changes in T1 and T2 relaxation times, and in the diffusion coefficient. CONCLUSIONS This study suggests a potential detection of changes to the bone marrow using a tabletop NMR device. Clinical translation may facilitate screening, early detection of bone weakening as a result of estrogen withdrawal, and monitoring of treatment efficacy. Magn Reson Med 78:860-870, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Yifat Sarda
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Elad Bergman
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Inbar Hillel
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Itzhak Binderman
- Department of Oral Biology, School of Dental Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Uri Nevo
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
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Stockmann JP, Cooley CZ, Guerin B, Rosen MS, Wald LL. Transmit Array Spatial Encoding (TRASE) using broadband WURST pulses for RF spatial encoding in inhomogeneous B0 fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 268:36-48. [PMID: 27155906 PMCID: PMC4909507 DOI: 10.1016/j.jmr.2016.04.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/17/2016] [Accepted: 04/07/2016] [Indexed: 06/01/2023]
Abstract
Transmit Array Spatial Encoding (TRASE) is a promising new MR encoding method that uses transmit RF (B1(+)) phase gradients over the field-of-view to perform Fourier spatial encoding. Acquisitions use a spin echo train in which the transmit coil phase ramp is modulated to jump from one k-space point to the next. This work extends the capability of TRASE by using swept radiofrequency (RF) pulses and a quadratic phase removal method to enable TRASE where it is arguably most needed: portable imaging systems with inhomogeneous B0 fields. The approach is particularly well-suited for portable MR scanners where (a) inhomogeneous B0 fields are a byproduct of lightweight magnet design, (b) heavy, high power-consumption gradient coil systems are a limitation to siting the system in non-conventional locations and (c) synergy with the use of spin echo trains is required to overcome intra-voxel dephasing (short T2(∗)) in the inhomogeneous field. TRASE does not use a modulation of the B0 field to encode, but it does suffer from secondary effects of the inhomogeneous field. Severe artifacts arise in TRASE images due to off-resonance effects when the RF pulse does not cover the full bandwidth of spin resonances in the imaging FOV. Thus, for highly inhomogeneous B0 fields, the peak RF power needed for high-bandwidth refocusing hard pulses becomes very expensive, in addition to requiring RF coils that can withstand thousands of volts. In this work, we use swept WURST RF pulse echo trains to achieve TRASE imaging in a highly inhomogeneous magnetic field (ΔB0/B0∼0.33% over the sample). By accurately exciting and refocusing the full bandwidth of spins, the WURST pulses eliminate artifacts caused by the limited bandwidth of the hard pulses used in previous realizations of TRASE imaging. We introduce a correction scheme to remove the unwanted quadratic phase modulation caused by the swept pulses. Also, a phase alternation scheme is employed to mitigate artifacts caused by mixture of the even and odd-echo coherence pathways due to defects in the refocusing pulse. In this paper, we describe this needed methodology and demonstrate the ability of TRASE to Fourier encode in an inhomogeneous field (ΔB0/B0∼1% over the full FOV).
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Affiliation(s)
- Jason P Stockmann
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, United States.
| | - Clarissa Z Cooley
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, United States
| | - Bastien Guerin
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, United States; Harvard Medical School, Boston, MA, United States
| | - Matthew S Rosen
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, United States; Department of Physics, Harvard University, Cambridge, MA 02141, United States; Harvard Medical School, Boston, MA, United States
| | - Lawrence L Wald
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, United States; Harvard Medical School, Boston, MA, United States
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Bergman E, Sarda Y, Ritz N, Sabo E, Navon G, Bergman R, Nevo U. In vivo assessment of aged human skin with a unilateral NMR scanner. NMR IN BIOMEDICINE 2015; 28:656-666. [PMID: 25900247 DOI: 10.1002/nbm.3304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 03/07/2015] [Accepted: 03/12/2015] [Indexed: 06/04/2023]
Abstract
Human skin undergoes morphological and biochemical changes as a result of chronological aging and exposure to solar ultraviolet irradiation (photoaging). Noninvasive detection of these changes may aid in the prevention and treatment of both types of aging. This article presents a noninvasive method for the evaluation of aging skin with a unilateral stray field NMR scanner. These portable and inexpensive scanners may be suitable for in-depth skin characterization. In vivo profiles of sun-protected and sun-exposed skin from the forearms of female subjects of different ages (n = 9) were measured. Skin biopsies for histopathological examination were used as reference. T2 analysis with a bi-exponential decay model was applied and the extracted parameters were examined as markers for dermal aging. In the upper reticular dermis, a significant increase in the fraction of the slow T2 component and in the T2 value itself was found to correlate with chronological aging. For most subjects, there was an additional increase in the values of the slow T2 component and the T2 values from the sun-exposed forearm, superimposed on that measured for the sun-protected forearm. These results are in agreement with the decline in collagen content and the increase in free water content with aging. The results suggest that such a technique can be used as a tool for the assessment of aging, and that bi-exponential fitting can produce sensitive fingerprint parameters for the dermal alterations that occur during aging.
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Affiliation(s)
- Elad Bergman
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978, Israel
| | - Yifat Sarda
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978, Israel
| | - Noa Ritz
- Department of Dermatology, Rambam Health Care Campus and The Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
| | - Edmond Sabo
- Department of Pathology, Rambam Health Care Campus and The Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
| | - Gil Navon
- School of Chemistry, Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Reuven Bergman
- Department of Dermatology, Rambam Health Care Campus and The Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
| | - Uri Nevo
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel-Aviv University, Ramat Aviv, Tel-Aviv 69978, Israel
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Oligschläger D, Lehmkuhl S, Watzlaw J, Benders S, de Boever E, Rehorn C, Vossel M, Schnakenberg U, Blümich B. Miniaturized multi-coil arrays for functional planar imaging with a single-sided NMR sensor. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 254:10-18. [PMID: 25771358 DOI: 10.1016/j.jmr.2015.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 06/04/2023]
Abstract
Nowadays most low-field NMR sensors, such as the single-sided Profile NMR-MOUSE®, still suffer from poor sensitivity, either resulting from low magnetic field strengths and correspondingly low NMR frequencies, or lack of sensitivity. Generally, micro-coils can improve sensitivity, but due to their small size, and thus small inductance, they are mainly used for high-field NMR. Their main application field is parallel imaging, where those coils are typically assembled to receive-only coil-arrays and increase the field-of-view. Prominent signal combination techniques such as GRAPPA and SENSE are used to combine the spatially independent NMR signals to images in order to increase acquisition speed. A decisive disadvantage of today's single-sided NMR probes is the limited accessibility for NMR imaging. Although it is possible to use flat gradient coils on top of the NMR-MOUSE® to apply imaging techniques, such images can only be recorded with very long acquisition times, excluding the NMR-MOUSE® for lateral imaging of time-dependent processes. In this study sensitivity improved micro-structured RF coils, optimized for low frequencies, and correspondingly arrays of these coils, were employed to improve sensitivity and gave access to lateral spatial resolution within the sensitive plane at several observation points at the same time. Recently developed three- and four-coil arrays were combined with a Profile NMR-MOUSE® and characterized in terms of coil coupling, noise correlation and signal combination. The three-coil array was used for lateral imaging of moisture transport in travertine rock samples and to study the one-dimensional drying of paint.
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Affiliation(s)
- Dirk Oligschläger
- Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, Worringer Weg 1, D-52074 Aachen, Germany.
| | - Sören Lehmkuhl
- Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, Worringer Weg 1, D-52074 Aachen, Germany
| | - Jan Watzlaw
- Institute of Materials in Electrical Engineering 1 (IWE 1), RWTH Aachen University, Sommerfeldstraße 24, D-52074 Aachen, Germany
| | - Stefan Benders
- Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, Worringer Weg 1, D-52074 Aachen, Germany
| | - Eva de Boever
- Department of Earth and Environmental Sciences, KU Leuven, Celestijnenlaan 200E, 3001 Leuven (Heverlee), Belgium
| | - Christian Rehorn
- Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, Worringer Weg 1, D-52074 Aachen, Germany
| | - Manuel Vossel
- Institute of Materials in Electrical Engineering 1 (IWE 1), RWTH Aachen University, Sommerfeldstraße 24, D-52074 Aachen, Germany
| | - Uwe Schnakenberg
- Institute of Materials in Electrical Engineering 1 (IWE 1), RWTH Aachen University, Sommerfeldstraße 24, D-52074 Aachen, Germany
| | - Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, Worringer Weg 1, D-52074 Aachen, Germany
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Zalesskiy SS, Danieli E, Blümich B, Ananikov VP. Miniaturization of NMR systems: desktop spectrometers, microcoil spectroscopy, and "NMR on a chip" for chemistry, biochemistry, and industry. Chem Rev 2014; 114:5641-94. [PMID: 24779750 DOI: 10.1021/cr400063g] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Sergey S Zalesskiy
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , Moscow, 119991, Russia
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Cooley CZ, Stockmann JP, Armstrong BD, Sarracanie M, Lev MH, Rosen MS, Wald LL. Two-dimensional imaging in a lightweight portable MRI scanner without gradient coils. Magn Reson Med 2014; 73:872-83. [PMID: 24668520 DOI: 10.1002/mrm.25147] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/02/2013] [Accepted: 01/05/2014] [Indexed: 11/06/2022]
Abstract
PURPOSE As the premiere modality for brain imaging, MRI could find wider applicability if lightweight, portable systems were available for siting in unconventional locations such as intensive care units, physician offices, surgical suites, ambulances, emergency rooms, sports facilities, or rural healthcare sites. METHODS We construct and validate a truly portable (<100 kg) and silent proof-of-concept MRI scanner which replaces conventional gradient encoding with a rotating lightweight cryogen-free, low-field magnet. When rotated about the object, the inhomogeneous field pattern is used as a rotating spatial encoding magnetic field (rSEM) to create generalized projections which encode the iteratively reconstructed two-dimensional (2D) image. Multiple receive channels are used to disambiguate the nonbijective encoding field. RESULTS The system is validated with experimental images of 2D test phantoms. Similar to other nonlinear field encoding schemes, the spatial resolution is position dependent with blurring in the center, but is shown to be likely sufficient for many medical applications. CONCLUSION The presented MRI scanner demonstrates the potential for portability by simultaneously relaxing the magnet homogeneity criteria and eliminating the gradient coil. This new architecture and encoding scheme shows convincing proof of concept images that are expected to be further improved with refinement of the calibration and methodology.
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Affiliation(s)
- Clarissa Zimmerman Cooley
- A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Horch C, Schlayer S, Stallmach F. High-pressure low-field 1H NMR relaxometry in nanoporous materials. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 240:24-33. [PMID: 24508760 DOI: 10.1016/j.jmr.2014.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 12/10/2013] [Accepted: 01/08/2014] [Indexed: 06/03/2023]
Abstract
A low-field NMR sensor with NdFeB permanent magnets (B0=118 mT) and a pressure cell made of PEEK (4 cm outer diameter) were designed for (1)H relaxation time studies of adsorbed molecules at pressures of up to 300 bar. The system was used to investigate methane uptake of microporous metal-organic frameworks and nanoporous activated carbon. T2 relaxation time distribution of pure methane and of methane under co-adsorption of carbon dioxide show that the host-guest interaction lead to a relaxation time contrasts, which may be used to distinguish between the gas phase and the different adsorbed phases of methane. Adsorption isotherms, exchange of methane between adsorbent particles and the surrounding gas phase, successive displacement of methane from adsorption sites by co-adsorption of carbon dioxide and CO2/CH4 adsorption separation factors were determined from the observed NMR relaxation time distributions.
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Affiliation(s)
- Carsten Horch
- University of Leipzig, Faculty for Physics and Earth Sciences, Linnstrae 5, 04103 Leipzig, Germany
| | - Stefan Schlayer
- University of Leipzig, Faculty for Physics and Earth Sciences, Linnstrae 5, 04103 Leipzig, Germany
| | - Frank Stallmach
- University of Leipzig, Faculty for Physics and Earth Sciences, Linnstrae 5, 04103 Leipzig, Germany.
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Mitchell J, Gladden LF, Chandrasekera TC, Fordham EJ. Low-field permanent magnets for industrial process and quality control. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2014; 76:1-60. [PMID: 24360243 DOI: 10.1016/j.pnmrs.2013.09.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 05/13/2023]
Abstract
In this review we focus on the technology associated with low-field NMR. We present the current state-of-the-art in low-field NMR hardware and experiments, considering general magnet designs, rf performance, data processing and interpretation. We provide guidance on obtaining the optimum results from these instruments, along with an introduction for those new to low-field NMR. The applications of lowfield NMR are now many and diverse. Furthermore, niche applications have spawned unique magnet designs to accommodate the extremes of operating environment or sample geometry. Trying to capture all the applications, methods, and hardware encompassed by low-field NMR would be a daunting task and likely of little interest to researchers or industrialists working in specific subject areas. Instead we discuss only a few applications to highlight uses of the hardware and experiments in an industrial environment. For details on more particular methods and applications, we provide citations to specialized review articles.
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Affiliation(s)
- J Mitchell
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom; Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
| | - L F Gladden
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom.
| | - T C Chandrasekera
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
| | - E J Fordham
- Schlumberger Gould Research, High Cross, Madingley Road, Cambridge CB3 0EL, United Kingdom
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Juchem C, Green D, de Graaf RA. Multi-coil magnetic field modeling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 236:95-104. [PMID: 24095841 PMCID: PMC3866212 DOI: 10.1016/j.jmr.2013.08.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 05/30/2023]
Abstract
The performance of multi-coil (MC) magnetic field modeling is compared to dedicated wire patterns for the generation of spherical harmonic (SH) shapes as these are the workhorse for spatial encoding and magnetic field homogenization in MR imaging and spectroscopy. To this end, an example 48 channel MC setup is analyzed and shown to be capable of generating all first through fourth order SH shapes over small and large regions-of-interest relevant for MR investigations. The MC efficiency for the generation of linear gradient fields shares the same order of magnitude with classic and state-of-the-art SH gradient coils. MC field modeling becomes progressively more efficient with the synthesis of more complex field shapes that require the combination of multiple SH terms. The possibility of a region-specific optimization of both magnetic field shapes and generation performance with the MC approach are discussed with emphasis on the possible trade-off between the field accuracy and generation efficiency. MC shimming has been shown previously to outperform current SH shimming. Along with the efficiency gains of MC shimming shown here, the MC concept has the potential to (1) replace conventional shim systems that are based on sets of dedicated SH coils and (2) allow optimal object-specific shim solutions similar to object-specific RF coils.
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Affiliation(s)
- Christoph Juchem
- Yale University School of Medicine, Department of Diagnostic Radiology, MR Research Center (MRRC), 300 Cedar Street, New Haven, CT 06520, USA.
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Liberman A, Bergman E, Sarda Y, Nevo U. Faster imaging with a portable unilateral NMR device. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 231:72-78. [PMID: 23597948 DOI: 10.1016/j.jmr.2013.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 03/18/2013] [Accepted: 03/21/2013] [Indexed: 06/02/2023]
Abstract
Unilateral NMR devices are important tools in various applications such as non-destructive testing and well logging, but are not applied routinely for imaging, primarily because B0 inhomogeneity in these scanners leads to a relatively low signal and requires use of the slow single point imaging scan scheme. Enabling high quality, fast imaging could make this affordable and portable technology practical for various imaging applications as well as for new applications that are not yet feasible with MRI technology. The goal of this work was to improve imaging times in a portable unilateral NMR scanner. Both Compressed Sensing and Fast Spin Echo were modified and applied to fit the unique characteristics of a unilateral device. Two printed phantoms, allowing high resolution images, were scanned with both methods and compared to a standard scan and to a low pass scan to evaluate performance. Both methods were found to be feasible with a unilateral device, proving ways to accelerate single point imaging in such scanners. This outcome encourages us to explore how to further accelerate imaging times in unilateral NMR devices so that this technology might become clinically applicable in the future.
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Affiliation(s)
- Asaf Liberman
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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