Journal of Magnetic Resonance Open最新文献

Comparison of different solvent suppression techniques for polymer characterization with a 90 MHz benchtop spectrometer 用90 MHz台式光谱仪比较不同溶剂抑制技术对聚合物的表征

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-12-19 DOI: 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 (ASR_norm). 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_norm 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.

在核磁共振光谱中，样品通常溶解在氘化溶剂中，以避免小的分析物信号与大的质子化溶剂信号重叠。然而，由于成本和广泛使用等原因，使用氘化溶剂是不切实际的，例如，对于流式NMR应用，因为需要大量的溶剂。本研究比较了六种不同的溶剂抑制技术：PRESATuration (PRESAT)，通过T1效应增强的水抑制（WET），脉冲梯度刺激回波（PGSTE）， 1脉冲破坏，简单溶剂减法，以及一种新开发的采集后抑制方法，称为傅里叶消除溶剂衰减（SAFE）。SAFE方法是基于对样品溶液和纯溶剂交替测量2n次，然后进行快速傅立叶变换以消除溶剂信号，该信号在第一次近似中是常数。对不同的溶剂抑制方法进行了单独和组合的比较，确定了最佳的抑制效果。通过将分析物与溶剂的比例归一化到未抑制的1H参考光谱（ASRnorm）来定量抑制。此外，比较了两种方法对不同摩尔质量聚合物溶液的适用性、定量对测量时间效率、重复性和中间精度的影响。PGSTE-SAFE组合被证明是聚合物样品最有效的方法，达到了约47,000的ASRnorm。通过研究非氘化溶剂中的聚苯乙烯，还评估了溶剂抑制方法在流动装置中的适用性。将WET、PGSTE和WET-PGSTE组合应用于在线粒径排除色谱-核磁共振（SECNMR）中，以证明它们在这种情况下有效抑制溶剂的潜力。

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引用次数: 0

The development of Magnetic Resonance Imaging (MRI) technology for use in space—A progress report 空间用磁共振成像技术的发展进展报告

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-12-16 DOI: 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.

十多年来，我们一直在开发适用于太空宇航员成像的磁共振成像（MRI）技术。该技术可归类为“无梯度”MRI，其工作原理是使用射频（RF）空间相位编码而不是通常的磁场梯度介导的空间频率编码。这里有一份进展报告，并概述了核磁共振成像在未来太空飞行中的应用地点和方式。到目前为止，我们已经为加拿大航天局（CSA）完成了几项设计概念研究，已经在零重力下飞行了一个原型，并开发了一种方法，可以实现CSA的健康超越MRI技术愿景。核磁共振成像在空间中的第一个应用将是研究空间飞行对人体的影响，特别是行星际辐射的影响。随后，核磁共振成像可以成为综合航天器医疗系统的核心部分，并用于诊断医疗目的。

引用次数: 0

Improving a low frequency EPR spectrometer using field-programmable gate array enabled direct digital detection 使用现场可编程门阵列改进低频EPR光谱仪，实现直接数字检测

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-11-01 DOI: 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.

基于现场可编程门阵列（FPGA）的高频直接数字检测（DDD）由于信号的高速实时处理而日益普及。因此，它为数字而不是模拟解调、滤波、正交检测和一般信号处理开辟了新的可能性，可以减少与热漂移、老化和等效模拟检测链布局相关的光谱仪噪声。本文介绍了两种信号检测方案在电子顺磁共振（EPR）移动式通用表面探测器（MOUSE）上对DPPH标准的低频电子顺磁共振（LFEPR）信噪比的比较结果。前者采用了LFEPR光谱仪经典的模拟检测解调方案，后者采用了苏黎世仪器的超高频锁相（UHFLI）放大器，取代了LFEPR光谱仪中的大部分模拟元件。与经典模拟系统相比，UHFLI光谱仪的配置将信噪比提高了2倍，将基线漂移降低到1 / 18，将仪器体积缩小了70%，仪器重量减少了50%。

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引用次数: 0

Long-term water migration in hydrated corn stalk pith and hemp stalk by 250 MHz NMR relaxometry and diffusometry 用250 MHz核磁共振弛豫仪和扩散仪研究水化玉米茎秆和大麻茎秆的长期水分迁移

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-09-04 DOI: 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)

T_{2}

relaxometry and diffusometry. Measurements were made every 6 h from

3 – 237

h, or until equilibrium. NMR

T_{2}

measured bound, intermediate bound and macropore water populations at two water mass hydrations. NMR diffusometry measured diffusion coefficients

D

of mobile water populations in each material. The diffusion coefficient

D

was acquired as a function of molecular migration time

Δ

to detect restricted diffusion.

D (Δ)

behavior indicated increased interpore connectivity in highly saturated hemp, versus swollen pores saturated pith.

D (Δ)

values were fit for surface to volume ratio

S / V

to determine average pore radius

r

as a function of hydration.

S / V

values were paired to

T_{2}

distributions to provide an effective average transverse magnetic surface relaxivity

{\bar{ρ}}_{2}

throughout hydration, which is then used to rescale

T_{2}

distributions as pore size distributions. Bound water was found in pores

< 1 μ

m, semi-bound water in pores from

1 – 30 μ

m and macropore water in pores from

30 – 300 μ

m, in agreement with prior literature.

植物纤维是目前生物复合材料的研究热点，已知植物纤维的亲水性，如玉米茎秆和大麻茎秆，需要进一步了解水对纤维结构的影响。利用核磁共振（NMR） T2弛豫仪和扩散仪将水化过程中这些纤维中的水分分布与纤维纤维素介质进行比较。从3-237 h每6 h测量一次，或直到平衡。核磁共振T2测量了两种水化水的结合层、中间结合层和大孔隙水的数量。核磁共振扩散测量法测量了每种物质中可移动水种群的扩散系数D。得到扩散系数D作为分子迁移时间的函数Δ来检测受限扩散。D（Δ）的行为表明，在高度饱和的大麻中，孔间连通性增加，而在饱和的髓中，孔肿胀。D（Δ）值适合于表面体积比S/V，以确定平均孔隙半径r作为水化的函数。将S/V值与T2分布配对，以提供水化过程中有效的平均横向磁表面弛豫率ρ´2，然后将其用于将T2分布重新缩放为孔径分布。1μm孔隙中存在束缚水，1 ~ 30μm孔隙中存在半束缚水，30 ~ 300μm孔隙中存在大孔隙水，与文献一致。

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引用次数: 0

Advanced NMR in contemporary China 当代中国先进核磁共振

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-09-01 DOI: 10.1016/j.jmro.2025.100209

Maili Liu , Lucio Frydman , Xueqian Kong , Conggang Li , Jun Xu

引用次数: 0

Efficient 15N hyperpolarization of [15N3]metronidazole antibiotic via spin-relayed pulsed SABRE-SHEATH 基于自旋继电器脉冲sabre -鞘的[15N3]甲硝唑抗生素高效15N超极化

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-07-24 DOI: 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 P_15N 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。

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引用次数: 0

Continuous-flow electron spin resonance microfluidics device with sub-nanoliter sample volume 亚纳升样品体积的连续流电子自旋共振微流体装置

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-07-09 DOI: 10.1016/j.jmro.2025.100207

Oleg Zgadzai , Nir Almog , Yefim Varshavsky , Moamen Jbara , Benoit Driesschaert , Aharon Blank

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.

本文提出了一种新型的连续流电子自旋共振（ESR）微流控装置，用于亚纳升液体样品的连续波（CW）和脉冲ESR测量。该系统集成了一个工作频率为~ 9.4 GHz的平面表面微谐振器（ParPar型）和一个精密制造的石英微流控芯片，使样品在谐振器的微波磁场热点内的空间限制成为可能，同时最大限度地减少介电损耗。有效样品体积为~ 0.06 nL，该设备支持标准微流体连接器，便于连续和停流实验。使用1 mM氘化芬兰三烷基（dFT）自由基水溶液，连续波ESR测量在80秒内获得的100点光谱的峰值信噪比（SNR）为~ 83，谐振器质量因子为Q ~ 15-20。这相当于自旋灵敏度为~ 1.04 × 109个自旋/√Hz/G。在0.1 W微波功率和10 ns π脉冲下进行的脉冲ESR测量中，SNR达到了~ 47，平均时间为1 s，对应于自旋灵敏度为~ 7.8 × 108自旋/√Hz。测量到的Rabi频率为~ 50 MHz，表明微波转换效率为~ 56 G/√W。脉冲自旋灵敏度和拉比频率与模拟值基本一致。该设备代表了基于esr的个体缓慢流动细胞检测的重要一步-类似于流式细胞术，但具有磁共振对比。随着未来的改进，如更高的工作频率、低温集成或优化的谐振器几何形状，该系统有望实现单细胞水平的实际ESR测量。

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引用次数: 0

Magnetic resonance coil prototyping and implementation for multi-nuclear small animal imaging 用于多核小动物成像的磁共振线圈原型设计与实现

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-07-09 DOI: 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.

目的异核磁共振成像可以对独特的疾病状态进行调查。这些方法通常需要为成像探头和目标定制的射频线圈设计。本研究解决了用于小动物成像应用的异核磁共振线圈快速成型的挑战。我们建议使用3d打印模具进行电感成形，通过柔性同轴电缆连接到印刷电路板（PCB），以提高线圈的可重复性和实用性。方法开发了一种快速成型管道，用于制造价格合理、灵敏度高的线圈。将3d打印模具电感器的再现性与手转电感器和PCB电感器进行了比较。在各种实际条件下验证了PCB/电感耦合对调谐/匹配条件影响的理论处理，产生了一种简化的方法，允许以最小的经验开发进行组件选择和组装。结果3d打印的模具电感器具有较高的再现性，其中PCB射频线圈的再现性最高。所有3d打印模具电感的平均谐振回波损耗（S11）为-40.2 dB±4.8 dB，平均电路Q因子为58±12。所提出的模型预测谐振特性在测量值的1%范围内的频率和几何形状。所开发的原型管道代表了一种快速有效的方法，用于设计具有所需共振频率和尺寸的高可重复性线圈，可以很容易地适应各种实验设置。所有设计资源-包括交互式线圈参数计算器，电感模具的3d模型和PCB文件-可在https://medcap.ai/mr-coil-calculator上使用。

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引用次数: 0

Hyperpolarized [1-¹³C] pyruvate MRSI reveals a diet-dependent metabolic shift in ZSF1 rats 超极化[1-¹³C]丙酮酸磁共振成像揭示了ZSF1大鼠饮食依赖性代谢转变

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-06-30 DOI: 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).

我们利用超极化（HP） [1-13C]丙酮酸磁共振成像（MRSI）技术，评估了喂食等热量高脂肪饮食与正常食物的Zucker自发性高血压脂肪（ZSF1）大鼠心脏代谢的变化。该技术利用显著的信号增强来跟踪注射HP [1-13C]丙酮酸在体内的代谢命运，允许同时评估多种代谢途径。[1-13C]丙酮酸转化为[1-13C]乳酸（Lac）反映厌氧糖酵解活性，而13c -碳酸氢盐（Bic）的检测表明葡萄糖氧化。我们的研究结果表明，相对于葡萄糖氧化，喂食高脂肪饮食的ZSF1大鼠更依赖于厌氧糖酵解，这种代谢转变可以在体内实时检测到。本研究证明了HP [1-13C]丙酮酸磁共振成像（MRSI）用于评估ZSF1肥胖大鼠心肌饮食依赖性代谢变化的可行性，ZSF1肥胖大鼠是一种广泛使用的具有保留射血分数（HFpEF）的心力衰竭临床前模型。

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引用次数: 0

Hyperpolarization: From toy to tool, and back to toy 超极化：从玩具到工具，再回到玩具

IF 2.624

Journal of Magnetic Resonance Open

Pub Date : 2025-06-01 DOI: 10.1016/j.jmro.2025.100202

Guinevere Mathies , Sami Jannin , Lucio Frydman

引用次数: 0