Pub Date : 2026-03-01Epub Date: 2025-12-16DOI: 10.1016/j.jmro.2025.100214
Gordon E. Sarty
We have been developing Magnetic Resonance Imaging (MRI) technology that is suitable for imaging astronauts in space for a little more than a decade. The technology may be classified as “gradient-free” MRI and works by using Radio Frequency (RF) spatial phase encoding instead of the usual magnetic field gradient mediated spatial frequency encoding. Here a progress report is given along with an outline of where and how MRI can be used in future space flight. To date we have completed several design concept studies for the Canadian Space Agency (CSA), have flown a prototype in zero-g and have developed an approach that can realize the CSA’s Health Beyond vision for the MRI technology. The first applications for MRI in space will be for research on the effects of space flight on the human body, especially that of interplanetary radiation. Following that, MRI can be a central part of an integrated spacecraft medical system and used for diagnostic medical purposes.
{"title":"The development of Magnetic Resonance Imaging (MRI) technology for use in space—A progress report","authors":"Gordon E. Sarty","doi":"10.1016/j.jmro.2025.100214","DOIUrl":"10.1016/j.jmro.2025.100214","url":null,"abstract":"<div><div>We have been developing Magnetic Resonance Imaging (MRI) technology that is suitable for imaging astronauts in space for a little more than a decade. The technology may be classified as “gradient-free” MRI and works by using Radio Frequency (RF) spatial phase encoding instead of the usual magnetic field gradient mediated spatial frequency encoding. Here a progress report is given along with an outline of where and how MRI can be used in future space flight. To date we have completed several design concept studies for the Canadian Space Agency (CSA), have flown a prototype in zero-g and have developed an approach that can realize the CSA’s Health Beyond vision for the MRI technology. The first applications for MRI in space will be for research on the effects of space flight on the human body, especially that of interplanetary radiation. Following that, MRI can be a central part of an integrated spacecraft medical system and used for diagnostic medical purposes.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"26 ","pages":"Article 100214"},"PeriodicalIF":2.624,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145898069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-19DOI: 10.1016/j.jmro.2025.100213
Johanna Tratz, Markus Matz, Manfred Wilhelm
In NMR spectroscopy, samples are usually dissolved in deuterated solvents to avoid overlap of small analyte signals with large, protonated solvent signals. However, for reasons such as cost and widespread use, using deuterated solvents is impractical, e.g., for on-flow NMR applications, since large volumes of solvent are required. This study compares six different solvent suppression techniques: PRESATuration (PRESAT), Water suppression Enhanced through T1 effects (WET), Pulsed Gradient STimulated Echo (PGSTE), 1-pulse-spoil, simple solvent subtraction, and a newly developed post-acquisition suppression method named Solvent Attenuation by Fourier Elimination (SAFE). The SAFE method is based on alternating measurements of the sample solution and the pure solvent 2n times, followed by a fast Fourier transform to eliminate the solvent signals, which are constant in the first approximation. The different solvent suppression methods were compared alone and in several combinations to determine their optimum suppression efficiency. The suppression was quantified by evaluating the Analyte-to-Solvent Ratio normalized to the unsuppressed 1H reference spectrum (ASRnorm). Furthermore, a comparison was made between the methods concerning their suitability for polymer solutions of varying molar masses, quantification towards measurement time efficiency, repeatability, and intermediate precision. The PGSTE-SAFE combination proved to be the most efficient method for polymer samples, achieving an ASRnorm of about 47,000. The applicability of solvent suppression methods in flow-based setups was also assessed by investigating polystyrenes in non-deuterated solvents. WET, PGSTE, and a WET-PGSTE combination were applied in online Size Exclusion Chromatography-NMR (SECNMR) to demonstrate their potential for efficient solvent suppression in this context.
{"title":"Comparison of different solvent suppression techniques for polymer characterization with a 90 MHz benchtop spectrometer","authors":"Johanna Tratz, Markus Matz, Manfred Wilhelm","doi":"10.1016/j.jmro.2025.100213","DOIUrl":"10.1016/j.jmro.2025.100213","url":null,"abstract":"<div><div>In NMR spectroscopy, samples are usually dissolved in deuterated solvents to avoid overlap of small analyte signals with large, protonated solvent signals. However, for reasons such as cost and widespread use, using deuterated solvents is impractical, e.g., for on-flow NMR applications, since large volumes of solvent are required. This study compares six different solvent suppression techniques: PRESATuration (PRESAT), Water suppression Enhanced through <em>T</em><sub>1</sub> effects (WET), Pulsed Gradient STimulated Echo (PGSTE), 1-pulse-spoil, simple solvent subtraction, and a newly developed post-acquisition suppression method named Solvent Attenuation by Fourier Elimination (SAFE). The SAFE method is based on alternating measurements of the sample solution and the pure solvent 2<sup>n</sup> times, followed by a fast Fourier transform to eliminate the solvent signals, which are constant in the first approximation. The different solvent suppression methods were compared alone and in several combinations to determine their optimum suppression efficiency. The suppression was quantified by evaluating the Analyte-to-Solvent Ratio normalized to the unsuppressed <sup>1</sup>H reference spectrum (ASR<sub>norm</sub>). Furthermore, a comparison was made between the methods concerning their suitability for polymer solutions of varying molar masses, quantification towards measurement time efficiency, repeatability, and intermediate precision. The PGSTE-SAFE combination proved to be the most efficient method for polymer samples, achieving an ASR<sub>norm</sub> of about 47,000. The applicability of solvent suppression methods in flow-based setups was also assessed by investigating polystyrenes in non-deuterated solvents. WET, PGSTE, and a WET-PGSTE combination were applied in online Size Exclusion Chromatography-NMR (SEC<img>NMR) to demonstrate their potential for efficient solvent suppression in this context.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"26 ","pages":"Article 100213"},"PeriodicalIF":2.624,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145898105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-09DOI: 10.1016/j.jmro.2026.100215
Hanna Wili , Nicholas Alaniva , Snædís Björgvinsdóttir, Alexander B. Barnes
Magic-angle spinning (MAS) partially averages anisotropic NMR interactions to improve spectral resolution of solid samples. MAS requires the sample to be spun precisely about an angle of 54.74° with respect to the magnetic field. This technique introduces components within MAS NMR radiofrequency probes that are distinguishable from their solution-state counterparts - most notably, a stator that spins and sets the angle of spinning axis. Here, we present an MAS stator that spins and pneumatically sets the spinning axis angle of a 6 mm spherical rotor (65µL sample volume) while inside a 10 mm solution-state NMR tube. 79Br experiments are used to verify the pneumatic adjustment and stability of the spinning angle, with 79Br spinning echoes from KBr observed out to 8 ms. Utility for solid state MAS NMR is then demonstrated by a 31P experiment of a proton-free inorganic phosphate, K4P2O7. Although this stator is applied here as an MAS insert that expands the utility of a solution-state probe, its compact design is advantageous for any spinning experiments in a restricted space.
{"title":"MAS NMR with a spherical rotor in a 10 mm NMR tube","authors":"Hanna Wili , Nicholas Alaniva , Snædís Björgvinsdóttir, Alexander B. Barnes","doi":"10.1016/j.jmro.2026.100215","DOIUrl":"10.1016/j.jmro.2026.100215","url":null,"abstract":"<div><div>Magic-angle spinning (MAS) partially averages anisotropic NMR interactions to improve spectral resolution of solid samples. MAS requires the sample to be spun precisely about an angle of 54.74° with respect to the magnetic field. This technique introduces components within MAS NMR radiofrequency probes that are distinguishable from their solution-state counterparts - most notably, a stator that spins and sets the angle of spinning axis. Here, we present an MAS stator that spins and pneumatically sets the spinning axis angle of a 6 mm spherical rotor (65µL sample volume) while inside a 10 mm solution-state NMR tube. <sup>79</sup>Br experiments are used to verify the pneumatic adjustment and stability of the spinning angle, with <sup>79</sup>Br spinning echoes from KBr observed out to 8 ms. Utility for solid state MAS NMR is then demonstrated by a <sup>31</sup>P experiment of a proton-free inorganic phosphate, K<sub>4</sub>P<sub>2</sub>O<sub>7</sub>. Although this stator is applied here as an MAS insert that expands the utility of a solution-state probe, its compact design is advantageous for any spinning experiments in a restricted space.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"26 ","pages":"Article 100215"},"PeriodicalIF":2.624,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-10DOI: 10.1016/j.jmro.2026.100216
Jasmin Schönzart , Alexander B. Barnes
We propose small and simplified magnets above 50 Tesla for wide dissemination to the NMR community. High temperature superconductor (HTS) with high current densities readily provide a viable path to a new generation of magnets for NMR which are smaller, better, and cheaper. A key innovation we foresee is the reduction of NMR magnet mandrels (a.k.a. winding bobbins) from typically employed diameter of >100 mm to smaller than 15 mm. Conventional NMR probes are far too large in diameter to fit into such small magnet bores and are unfavorably long due to the distance from the homogenous region of the magnet to the edge of the bore. Instead, we envision narrow (<10 mm diameter) and short (<20 mm length) extensions of the probe inside the magnet bore. Additionally, interior to the bore will be a stator housing a magic angle spinning (MAS) sphere. Exterior to the bore, radio frequency circuity and other probe component dimensions will therefore be unrestricted, and uncoupled, from magnet geometry. Moreover, MAS spheres together with narrow bore HTS magnets will be the keystone technology enabling solid state NMR above 50 Tesla. We also consider effects of magnetic susceptibility and symmetry of components near the sample to ultimately acquire high-resolution NMR spectra. Possible avenues for thermal isolation between the magnet and sample are considered for experiments in a temperature range of 4 to 400 Kelvin. These magnets will be small enough to fit in the palm of your hand. Shrinking the overall size of NMR magnets will improve dissemination as the production costs and required laboratory space will be significantly smaller. The small magnets will have 5 Gauss radii of less than a meter without active shielding—making them easier to site and easier to manufacture. With this new paradigm of enhanced technology, NMR spectroscopists will be well-positioned to push the frontiers of science ahead in the future.
{"title":"Miniaturized magnets for NMR above 50 tesla","authors":"Jasmin Schönzart , Alexander B. Barnes","doi":"10.1016/j.jmro.2026.100216","DOIUrl":"10.1016/j.jmro.2026.100216","url":null,"abstract":"<div><div>We propose small and simplified magnets above 50 Tesla for wide dissemination to the NMR community. High temperature superconductor (HTS) with high current densities readily provide a viable path to a new generation of magnets for NMR which are smaller, better, and cheaper. A key innovation we foresee is the reduction of NMR magnet mandrels (a.k.a. winding bobbins) from typically employed diameter of >100 mm to smaller than 15 mm. Conventional NMR probes are far too large in diameter to fit into such small magnet bores and are unfavorably long due to the distance from the homogenous region of the magnet to the edge of the bore. Instead, we envision narrow (<10 mm diameter) and short (<20 mm length) extensions of the probe inside the magnet bore. Additionally, interior to the bore will be a stator housing a magic angle spinning (MAS) sphere. Exterior to the bore, radio frequency circuity and other probe component dimensions will therefore be unrestricted, and uncoupled, from magnet geometry. Moreover, MAS spheres together with narrow bore HTS magnets will be the keystone technology enabling solid state NMR above 50 Tesla. We also consider effects of magnetic susceptibility and symmetry of components near the sample to ultimately acquire high-resolution NMR spectra. Possible avenues for thermal isolation between the magnet and sample are considered for experiments in a temperature range of 4 to 400 Kelvin. These magnets will be small enough to fit in the palm of your hand. Shrinking the overall size of NMR magnets will improve dissemination as the production costs and required laboratory space will be significantly smaller. The small magnets will have 5 Gauss radii of less than a meter without active shielding—making them easier to site and easier to manufacture. With this new paradigm of enhanced technology, NMR spectroscopists will be well-positioned to push the frontiers of science ahead in the future.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"26 ","pages":"Article 100216"},"PeriodicalIF":2.624,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147421229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-01DOI: 10.1016/j.jmro.2025.100212
Joseph P. Hornak , James D. Phillips , Arash Fereidouni
Field-programmable gate array (FPGA) enabled direct digital detection (DDD) at higher frequencies is becoming increasingly available and popular due to the high-speed real-time signal processing. Consequently, it is opening up new possibilities for digital rather than analog demodulation, filtering, quadrature detection, and general signal processing that can reduce the spectrometer noise associated with thermal drift, aging, and layout of the equivalent analog detection chain. This article presents the result of a comparison of the low-frequency electron paramagnetic resonance (LFEPR) signal-to-noise ratio for a DPPH standard on the electron paramagnetic resonance (EPR) mobile universal surface explorer (MOUSE) by two signal detection schemes. The first utilized the classic analog detection and demodulation scheme of a LFEPR spectrometer and the second utilized the Zurich Instruments ultra-high frequency lock-in (UHFLI) amplifier, which replaces most of the analog components in the LFEPR spectrometer. The UHFLI spectrometer configuration improved the signal-to-noise ratio by a factor of two, reduced the baseline drift to one eighteenth, reduced the instrument volume by 70 %, and reduced the instrument weight by 50 % compared to the values with the classic analog system.
{"title":"Improving a low frequency EPR spectrometer using field-programmable gate array enabled direct digital detection","authors":"Joseph P. Hornak , James D. Phillips , Arash Fereidouni","doi":"10.1016/j.jmro.2025.100212","DOIUrl":"10.1016/j.jmro.2025.100212","url":null,"abstract":"<div><div>Field-programmable gate array (FPGA) enabled direct digital detection (DDD) at higher frequencies is becoming increasingly available and popular due to the high-speed real-time signal processing. Consequently, it is opening up new possibilities for digital rather than analog demodulation, filtering, quadrature detection, and general signal processing that can reduce the spectrometer noise associated with thermal drift, aging, and layout of the equivalent analog detection chain. This article presents the result of a comparison of the low-frequency electron paramagnetic resonance (LFEPR) signal-to-noise ratio for a DPPH standard on the electron paramagnetic resonance (EPR) mobile universal surface explorer (MOUSE) by two signal detection schemes. The first utilized the classic analog detection and demodulation scheme of a LFEPR spectrometer and the second utilized the Zurich Instruments ultra-high frequency lock-in (UHFLI) amplifier, which replaces most of the analog components in the LFEPR spectrometer. The UHFLI spectrometer configuration improved the signal-to-noise ratio by a factor of two, reduced the baseline drift to one eighteenth, reduced the instrument volume by 70 %, and reduced the instrument weight by 50 % compared to the values with the classic analog system.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"25 ","pages":"Article 100212"},"PeriodicalIF":2.624,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-09-04DOI: 10.1016/j.jmro.2025.100210
Matthew C. Young , Sarah L. Codd , Joseph D. Seymour
Plant fibers are of current interest in biocomposites and known hydrophilicity of plant fibers, e.g. corn stalk pith and hemp stalk, require enhanced understanding of water impacts on fiber structure. Water distribution during hydration in these fibers is compared to fibrous cellulose media using nuclear magnetic resonance (NMR) relaxometry and diffusometry. Measurements were made every 6 h from h, or until equilibrium. NMR measured bound, intermediate bound and macropore water populations at two water mass hydrations. NMR diffusometry measured diffusion coefficients of mobile water populations in each material. The diffusion coefficient was acquired as a function of molecular migration time to detect restricted diffusion. behavior indicated increased interpore connectivity in highly saturated hemp, versus swollen pores saturated pith. values were fit for surface to volume ratio to determine average pore radius as a function of hydration. values were paired to distributions to provide an effective average transverse magnetic surface relaxivity throughout hydration, which is then used to rescale distributions as pore size distributions. Bound water was found in pores m, semi-bound water in pores from m and macropore water in pores from m, in agreement with prior literature.
{"title":"Long-term water migration in hydrated corn stalk pith and hemp stalk by 250 MHz NMR relaxometry and diffusometry","authors":"Matthew C. Young , Sarah L. Codd , Joseph D. Seymour","doi":"10.1016/j.jmro.2025.100210","DOIUrl":"10.1016/j.jmro.2025.100210","url":null,"abstract":"<div><div>Plant fibers are of current interest in biocomposites and known hydrophilicity of plant fibers, e.g. corn stalk pith and hemp stalk, require enhanced understanding of water impacts on fiber structure. Water distribution during hydration in these fibers is compared to fibrous cellulose media using nuclear magnetic resonance (NMR) <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> relaxometry and diffusometry. Measurements were made every 6 h from <span><math><mrow><mn>3</mn><mtext>–</mtext><mn>237</mn></mrow></math></span> h, or until equilibrium. NMR <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> measured bound, intermediate bound and macropore water populations at two water mass hydrations. NMR diffusometry measured diffusion coefficients <span><math><mi>D</mi></math></span> of mobile water populations in each material. The diffusion coefficient <span><math><mi>D</mi></math></span> was acquired as a function of molecular migration time <span><math><mi>Δ</mi></math></span> to detect restricted diffusion. <span><math><mrow><mi>D</mi><mrow><mo>(</mo><mi>Δ</mi><mo>)</mo></mrow></mrow></math></span> behavior indicated increased interpore connectivity in highly saturated hemp, versus swollen pores saturated pith. <span><math><mrow><mi>D</mi><mrow><mo>(</mo><mi>Δ</mi><mo>)</mo></mrow></mrow></math></span> values were fit for surface to volume ratio <span><math><mrow><mi>S</mi><mo>/</mo><mi>V</mi></mrow></math></span> to determine average pore radius <span><math><mi>r</mi></math></span> as a function of hydration. <span><math><mrow><mi>S</mi><mo>/</mo><mi>V</mi></mrow></math></span> values were paired to <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> distributions to provide an effective average transverse magnetic surface relaxivity <span><math><msub><mrow><mover><mrow><mi>ρ</mi></mrow><mrow><mo>̄</mo></mrow></mover></mrow><mrow><mn>2</mn></mrow></msub></math></span> throughout hydration, which is then used to rescale <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> distributions as pore size distributions. Bound water was found in pores <span><math><mrow><mo><</mo><mn>1</mn><mspace></mspace><mi>μ</mi></mrow></math></span>m, semi-bound water in pores from <span><math><mrow><mn>1</mn><mtext>–</mtext><mn>30</mn><mspace></mspace><mi>μ</mi></mrow></math></span>m and macropore water in pores from <span><math><mrow><mn>30</mn><mtext>–</mtext><mn>300</mn><mspace></mspace><mi>μ</mi></mrow></math></span>m, in agreement with prior literature.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"25 ","pages":"Article 100210"},"PeriodicalIF":2.624,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-07-24DOI: 10.1016/j.jmro.2025.100208
Shiraz Nantogma , Shannon L. Eriksson , Thomas Theis , Warren S. Warren , Boyd M. Goodson , Eduard Y. Chekmenev
Signal Amplification by Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) is an NMR hyperpolarization technique that relies of the simultaneous exchange of parahydrogen and a to-be-hyperpolarized molecule on the metal center of a polarization-transfer catalyst in a microtesla magnetic field. Until recently, this method has been understood to perform hyperpolarization by establishing level anti-crossings between the nuclear spins of the parahydrogen derived hydrides (acting as a source of hyperpolarization) and those of the substrate. Recently, the application of highly non-intuitive pulse sequences (comprising pulses of microtesla DC fields) was predicted to hyperpolarize nuclear spins more efficiently than the canonical (static-field) SABRE-SHEATH approach. Here we show that by employing a basic “on-off” pulse sequence of rectangular microtesla pulses, it is possible to improve the hyperpolarization efficiency for SABRE-SHEATH of [15N3]metronidazole, an FDA-approved antibiotic (in non-enriched and non-hyperpolarized form) and potential hypoxia sensing molecule. Specifically, we demonstrate that 15N polarization of 18.5 % can be obtained in 80 s of parahydrogen bubbling parahydrogen through a solution containing 20 mM [15N3]metronidazole. In practice, (1.32 ± 0.14)-fold improvements in P15N was obtained with the pulsed method described here compared to static field technique variant. These results show that pulsed SABRE-SHEATH was successfully applied to 15N-labeled biologically relevant molecule. Moreover, we also demonstrate that although the pulsed SABRE-SHEATH sequence was designed for polarization transfer from parahydrogen derived hydrides to the metronidazole’s 15N catalyst-binding site, all three 15N sites of [15N3]metronidazole attained the hyperpolarized state. This spin-relayed polarization transfer becomes possible due to the 15N relay network established by their spin-spin J-couplings. The feasibility of the spin-relayed polarization transfer is demonstrated here for the first time for pulsed SABRE-SHEATH (as opposed to the static-field SABRE-SHEATH reported previously) and it paves the way to broad applicability of the technique.
在微特斯拉磁场中，对氢和待超极化分子在极化转移催化剂的金属中心上同时交换，从而实现了一种核磁共振超极化技术。直到最近，这种方法已经被理解为通过在对氢衍生的氢化物（作为超极化源）和底物的核自旋之间建立水平反交叉来实现超极化。最近，预测应用高度非直观的脉冲序列（包括微特斯拉直流场脉冲）比规范的（静态场）SABRE-SHEATH方法更有效地超极化核自旋。本研究表明，通过使用矩形微特斯拉脉冲的基本“开-关”脉冲序列，可以提高[15N3]甲硝唑的SABRE-SHEATH的超极化效率，[15N3]甲硝唑是fda批准的抗生素（非富集和非超极化形式）和潜在的缺氧传感分子。具体来说，我们证明了在含有20 mM [15N3]甲硝唑的溶液中，对氢鼓泡80秒内可以获得18.5%的15N极化。在实践中，与静态场技术相比，脉冲法获得了（1.32±0.14）倍的P15N改善。这些结果表明，脉冲SABRE-SHEATH成功地应用于15n标记的生物相关分子。此外，我们还证明，虽然脉冲sabre -鞘序列被设计用于从对氢衍生氢化物到甲硝唑的15N催化结合位点的极化转移，但[15N3]甲硝唑的所有三个15N位点都达到了超极化状态。自旋-自旋j型耦合建立的15N中继网络使这种自旋中继极化转移成为可能。本文首次证明了脉冲SABRE-SHEATH（与之前报道的静态场SABRE-SHEATH相反）自旋中继极化转移的可行性，为该技术的广泛应用铺平了道路。
{"title":"Efficient 15N hyperpolarization of [15N3]metronidazole antibiotic via spin-relayed pulsed SABRE-SHEATH","authors":"Shiraz Nantogma , Shannon L. Eriksson , Thomas Theis , Warren S. Warren , Boyd M. Goodson , Eduard Y. Chekmenev","doi":"10.1016/j.jmro.2025.100208","DOIUrl":"10.1016/j.jmro.2025.100208","url":null,"abstract":"<div><div>Signal Amplification by Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) is an NMR hyperpolarization technique that relies of the simultaneous exchange of parahydrogen and a to-be-hyperpolarized molecule on the metal center of a polarization-transfer catalyst in a microtesla magnetic field. Until recently, this method has been understood to perform hyperpolarization by establishing level anti-crossings between the nuclear spins of the parahydrogen derived hydrides (acting as a source of hyperpolarization) and those of the substrate. Recently, the application of highly non-intuitive pulse sequences (comprising pulses of microtesla DC fields) was predicted to hyperpolarize nuclear spins more efficiently than the canonical (static-field) SABRE-SHEATH approach. Here we show that by employing a basic “on-off” pulse sequence of rectangular microtesla pulses, it is possible to improve the hyperpolarization efficiency for SABRE-SHEATH of [<sup>15</sup>N<sub>3</sub>]metronidazole, an FDA-approved antibiotic (in non-enriched and non-hyperpolarized form) and potential hypoxia sensing molecule. Specifically, we demonstrate that <sup>15</sup>N polarization of 18.5 % can be obtained in 80 s of parahydrogen bubbling parahydrogen through a solution containing 20 mM [<sup>15</sup>N<sub>3</sub>]metronidazole. In practice, (1.32 ± 0.14)-fold improvements in <em>P</em><sub>15N</sub> was obtained with the pulsed method described here compared to static field technique variant. These results show that pulsed SABRE-SHEATH was successfully applied to <sup>15</sup>N-labeled biologically relevant molecule. Moreover, we also demonstrate that although the pulsed SABRE-SHEATH sequence was designed for polarization transfer from parahydrogen derived hydrides to the metronidazole’s <sup>15</sup>N catalyst-binding site, all three <sup>15</sup>N sites of [<sup>15</sup>N<sub>3</sub>]metronidazole attained the hyperpolarized state. This spin-relayed polarization transfer becomes possible due to the <sup>15</sup>N relay network established by their spin-spin <em>J</em>-couplings. The feasibility of the spin-relayed polarization transfer is demonstrated here for the first time for pulsed SABRE-SHEATH (as opposed to the static-field SABRE-SHEATH reported previously) and it paves the way to broad applicability of the technique.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"24 ","pages":"Article 100208"},"PeriodicalIF":2.624,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-06-30DOI: 10.1016/j.jmro.2025.100205
Karen Dos Santos , Salva R. Yurista , Sophia M. Mirrione , David O. Guarin Bedoya , Samuel R. Calos , Ivan Luptak , Atsushi M. Takahashi , Wai Hong Wilson Tang , Yoshiko Iwamoto , Christopher T. Nguyen , Yi-Fen Yen
We evaluated altered cardiac metabolism in Zucker Spontaneously Hypertensive Fatty (ZSF1) rats fed an isocaloric high-fat diet versus normal chow using hyperpolarized (HP) [1-13C]pyruvate MR spectroscopic imaging (MRSI). This technique exploits remarkable signal enhancement to track the metabolic fate of injected HP [1-13C]pyruvate in vivo, allowing a simultaneous assessment of multiple metabolic pathways. The conversion of [1-13C]pyruvate to [1-13C]lactate (Lac) reflects anaerobic glycolysis activity, while the detection of 13C-bicarbonate (Bic) indicates glucose oxidation. Our findings show that ZSF1 rats fed a high-fat diet exhibit a greater reliance on anaerobic glycolysis relative to glucose oxidation, and this metabolic shift can be detected in vivo in real time. This study demonstrates the feasibility of HP [1-13C]pyruvate MRSI for assessing diet-dependent metabolic shifts in the myocardium of ZSF1 obese rats, a widely used preclinical model for heart failure with preserved ejection fraction (HFpEF).
{"title":"Hyperpolarized [1-¹³C] pyruvate MRSI reveals a diet-dependent metabolic shift in ZSF1 rats","authors":"Karen Dos Santos , Salva R. Yurista , Sophia M. Mirrione , David O. Guarin Bedoya , Samuel R. Calos , Ivan Luptak , Atsushi M. Takahashi , Wai Hong Wilson Tang , Yoshiko Iwamoto , Christopher T. Nguyen , Yi-Fen Yen","doi":"10.1016/j.jmro.2025.100205","DOIUrl":"10.1016/j.jmro.2025.100205","url":null,"abstract":"<div><div>We evaluated altered cardiac metabolism in Zucker Spontaneously Hypertensive Fatty (ZSF1) rats fed an isocaloric high-fat diet versus normal chow using hyperpolarized (HP) [1-<sup>13</sup>C]pyruvate MR spectroscopic imaging (MRSI). This technique exploits remarkable signal enhancement to track the metabolic fate of injected HP [1-<sup>13</sup>C]pyruvate <em>in vivo</em>, allowing a simultaneous assessment of multiple metabolic pathways. The conversion of [1-<sup>13</sup>C]pyruvate to [1-<sup>13</sup>C]lactate (Lac) reflects anaerobic glycolysis activity, while the detection of <sup>13</sup>C-bicarbonate (Bic) indicates glucose oxidation<em>.</em> Our findings show that ZSF1 rats fed a high-fat diet exhibit a greater reliance on anaerobic glycolysis relative to glucose oxidation, and this metabolic shift can be detected <em>in vivo</em> in real time. This study demonstrates the feasibility of HP [1-<sup>13</sup>C]pyruvate MRSI for assessing diet-dependent metabolic shifts in the myocardium of ZSF1 obese rats, a widely used preclinical model for heart failure with preserved ejection fraction (HFpEF).</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"24 ","pages":"Article 100205"},"PeriodicalIF":2.624,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-07-09DOI: 10.1016/j.jmro.2025.100206
Alexander I. Zavriyev , Benjamin J. Yoon , John Choi , Bukola Y. Adebesin , Paul S. Jacobs , Gabor Mizsei , Molly M. Sheehan , Stephen Kadlecek , Terence P.F. Gade
Purpose
Heteronuclear MR imaging allows investigation into unique disease states. These approaches often require radiofrequency coil designs that are customized for the imaging probe and target. This study addresses the challenges of rapidly prototyping heteronuclear MR coils for small animal imaging applications. We propose the use of 3D-printing molds for inductor shaping connected to a printed circuit board (PCB) via a flexible coaxial cabling to enhance coil reproducibility and utility.
Methods
A rapid prototyping pipeline was developed for constructing affordable and sensitive coils. The reproducibility of 3D-printed mold inductors was compared to hand-turned and PCB inductors. A theoretical treatment of the effect of PCB/inductor coupling on tuning/matching conditions was verified under a variety of practical conditions, yielding a simplified approach which allows component selection and assembly with minimal empirical development.
Results
The 3D-printed mold inductors demonstrated higher reproducibility than hand-turned inductors, and PCB RF coils demonstrated the highest reproducibility. The average resonance return loss (S11) across all 3D-printed mold inductors was -40.2 dB ± 4.8 dB, with an average circuit Q factor of 58 ± 12. The presented model predicts resonance characteristics within 1 % of measured values over a range of frequencies and geometries.
Conclusion
The developed prototyping pipeline represents a rapid and effective approach for designing highly reproducible coils with a desired resonance frequency and size that can easily be adapted for a variety of experimental set-ups. All design resources – including an interactive coil-parameter calculator, 3D-models of inductor molds, and PCB files – are available for use at https://medcap.ai/mr-coil-calculator.
{"title":"Magnetic resonance coil prototyping and implementation for multi-nuclear small animal imaging","authors":"Alexander I. Zavriyev , Benjamin J. Yoon , John Choi , Bukola Y. Adebesin , Paul S. Jacobs , Gabor Mizsei , Molly M. Sheehan , Stephen Kadlecek , Terence P.F. Gade","doi":"10.1016/j.jmro.2025.100206","DOIUrl":"10.1016/j.jmro.2025.100206","url":null,"abstract":"<div><h3>Purpose</h3><div>Heteronuclear MR imaging allows investigation into unique disease states. These approaches often require radiofrequency coil designs that are customized for the imaging probe and target. This study addresses the challenges of rapidly prototyping heteronuclear MR coils for small animal imaging applications. We propose the use of 3D-printing molds for inductor shaping connected to a printed circuit board (PCB) via a flexible coaxial cabling to enhance coil reproducibility and utility.</div></div><div><h3>Methods</h3><div>A rapid prototyping pipeline was developed for constructing affordable and sensitive coils. The reproducibility of 3D-printed mold inductors was compared to hand-turned and PCB inductors. A theoretical treatment of the effect of PCB/inductor coupling on tuning/matching conditions was verified under a variety of practical conditions, yielding a simplified approach which allows component selection and assembly with minimal empirical development.</div></div><div><h3>Results</h3><div>The 3D-printed mold inductors demonstrated higher reproducibility than hand-turned inductors, and PCB RF coils demonstrated the highest reproducibility. The average resonance return loss (S<sub>11</sub>) across all 3D-printed mold inductors was -40.2 dB ± 4.8 dB, with an average circuit Q factor of 58 ± 12. The presented model predicts resonance characteristics within 1 % of measured values over a range of frequencies and geometries.</div></div><div><h3>Conclusion</h3><div>The developed prototyping pipeline represents a rapid and effective approach for designing highly reproducible coils with a desired resonance frequency and size that can easily be adapted for a variety of experimental set-ups. All design resources – including an interactive coil-parameter calculator, 3D-models of inductor molds, and PCB files – are available for use at <span><span>https://medcap.ai/mr-coil-calculator</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"24 ","pages":"Article 100206"},"PeriodicalIF":2.624,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144613919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a novel continuous-flow electron spin resonance (ESR) microfluidic device designed for both continuous-wave (CW) and pulsed ESR measurements on sub-nanoliter liquid samples. The system integrates a planar surface microresonator (ParPar type) operating at ∼9.4 GHz with a precision-fabricated quartz microfluidic chip, enabling spatial confinement of the sample within the resonator’s microwave magnetic field hotspot while minimizing dielectric losses. The effective sample volume is ∼0.06 nL, and the device supports standard microfluidic connectors, facilitating both continuous and stopped-flow experiments. Using a 1 mM aqueous solution of deuterated Finland trityl (dFT) radical, CW ESR measurements yielded a peak signal-to-noise ratio (SNR) of ∼83 for a 100-point spectrum acquired over 80 s, with a resonator quality factor of Q ∼15–20. This corresponds to a spin sensitivity of ∼1.04 × 109 spins/√Hz/G. Pulsed ESR measurements, performed with 0.1 W microwave power and 10 ns π pulses, achieved an SNR of ∼47 with 1 s of averaging, corresponding to a spin sensitivity of ∼7.8 × 108 spins/√Hz. A Rabi frequency of ∼50 MHz was measured, indicating a microwave conversion efficiency of ∼56 G/√W. Both the pulsed spin sensitivity and Rabi frequency are consistent with simulated values. This device represents a significant step toward ESR-based detection of individual, slowly flowing cells—analogous to flow cytometry but with magnetic resonance contrast. With future enhancements such as higher operating frequencies, cryogenic integration, or optimized resonator geometries, the system is expected to enable practical ESR measurements at the single-cell level.
{"title":"Continuous-flow electron spin resonance microfluidics device with sub-nanoliter sample volume","authors":"Oleg Zgadzai , Nir Almog , Yefim Varshavsky , Moamen Jbara , Benoit Driesschaert , Aharon Blank","doi":"10.1016/j.jmro.2025.100207","DOIUrl":"10.1016/j.jmro.2025.100207","url":null,"abstract":"<div><div>This paper presents a novel continuous-flow electron spin resonance (ESR) microfluidic device designed for both continuous-wave (CW) and pulsed ESR measurements on sub-nanoliter liquid samples. The system integrates a planar surface microresonator (ParPar type) operating at ∼9.4 GHz with a precision-fabricated quartz microfluidic chip, enabling spatial confinement of the sample within the resonator’s microwave magnetic field hotspot while minimizing dielectric losses. The effective sample volume is ∼0.06 nL, and the device supports standard microfluidic connectors, facilitating both continuous and stopped-flow experiments. Using a 1 mM aqueous solution of deuterated Finland trityl (dFT) radical, CW ESR measurements yielded a peak signal-to-noise ratio (SNR) of ∼83 for a 100-point spectrum acquired over 80 s, with a resonator quality factor of Q ∼15–20. This corresponds to a spin sensitivity of ∼1.04 × 10<sup>9</sup> spins/√Hz/G. Pulsed ESR measurements, performed with 0.1 W microwave power and 10 ns π pulses, achieved an SNR of ∼47 with 1 s of averaging, corresponding to a spin sensitivity of ∼7.8 × 10<sup>8</sup> spins/√Hz. A Rabi frequency of ∼50 MHz was measured, indicating a microwave conversion efficiency of ∼56 G/√W. Both the pulsed spin sensitivity and Rabi frequency are consistent with simulated values. This device represents a significant step toward ESR-based detection of individual, slowly flowing cells—analogous to flow cytometry but with magnetic resonance contrast. With future enhancements such as higher operating frequencies, cryogenic integration, or optimized resonator geometries, the system is expected to enable practical ESR measurements at the single-cell level.</div></div>","PeriodicalId":365,"journal":{"name":"Journal of Magnetic Resonance Open","volume":"24 ","pages":"Article 100207"},"PeriodicalIF":2.624,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144604406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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