On the spin order transfer from parahydrogen to another nucleus

Bär, Sébastien; Lange, Thomas; Leibfritz, Dieter; Hennig, Jürgen; Elverfeldt, Dominik von; Hövener, Jan‐Bernd

doi:10.1016/j.jmr.2012.08.016

Cited by 72 publications

(67 citation statements)

References 30 publications

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“…As predicted by Bär et al 32,. the l-PH-INEPT+ sequence enabled the production of longitudinal magnetization hyperpolarized to a similar level, P =(19±2) % (detected 2 s after generation, for 5.54 mM HEP in D 2 O) (Fig.…”

Section: Resultssupporting

confidence: 74%

Liquid-state carbon-13 hyperpolarization generated in an MRI system for fast imaging

et al. 2017

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Hyperpolarized (HP) tracers dramatically increase the sensitivity of magnetic resonance imaging (MRI) to monitor metabolism non-invasively and in vivo. Their production, however, requires an extra polarizing device (polarizer) whose complexity, operation and cost can exceed that of an MRI system itself. Furthermore, the lifetime of HP tracers is short and some of the enhancement is lost during transfer to the application site. Here, we present the production of HP tracers in water without an external polarizer: by Synthesis Amid the Magnet Bore, A Dramatically Enhanced Nuclear Alignment (SAMBADENA) is achieved within seconds, corresponding to a hyperpolarization of ∼20%. As transfer of the tracer is no longer required, SAMBADENA may permit a higher polarization at the time of detection at a fraction of the cost and complexity of external polarizers. This development is particularly promising in light of the recently extended portfolio of biomedically relevant para-hydrogen-tracers and may lead to new diagnostic applications.

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Section: Resultssupporting

confidence: 74%

Liquid-state carbon-13 hyperpolarization generated in an MRI system for fast imaging

et al. 2017

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“…[21c, 30] Other approaches aimed at improving the polarization transfer efficiency into a wide range of J-coupling constants [31] and to increase the stability with respect to inaccurate pulses and delays. [32] …”

Section: How It Work: Principles Of Parahydrogen-based Polarizationmentioning

confidence: 99%

“…[34] To support these technologies, a diverse range of rf SOT sequences for production of HP CAs have been introduced and validated. [30a, 31–32, 33b, 33c, 58a] …”

Section: How To Make It Work: the Hyperpolarizer And Chemistry Of mentioning

confidence: 99%

Parahydrogen‐Based Hyperpolarization for Biomedicine

et al. 2018

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Magnetic resonance (MR) is one of the most versatile and useful physical effects used for human imaging, chemical analysis, and the elucidation of molecular structures. However, its full potential is rarely used, because only a small fraction of the nuclear spin ensemble is polarized, that is, aligned with the applied static magnetic field. Hyperpolarization methods seek other means to increase the polarization and thus the MR signal. A unique source of pure spin order is the entangled singlet spin state of dihydrogen, parahydrogen (pH ), which is inherently stable and long-lived. When brought into contact with another molecule, this "spin order on demand" allows the MR signal to be enhanced by several orders of magnitude. Considerable progress has been made in the past decade in the area of pH -based hyperpolarization techniques for biomedical applications. It is the goal of this Review to provide a selective overview of these developments, covering the areas of spin physics, catalysis, instrumentation, preparation of the contrast agents, and applications.

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“…The spectrometer-based architecture should also enable the experimental parameter space to be systematically explored for further improvement of signal enhancement [35, 57]. In terms of reproducibility, this experimental setup has performed predictably and has consistently yielded high polarization levels on the order of twenty percent or more in PHIP experiments.…”

Section: Resultsmentioning

confidence: 99%

“…Following chemical addition of parahydrogen to the PHIP precursors, decoupling was turned off and a pulse sequence was applied to transform the singlet-state spin order of parahydrogen into net heteronuclear magnetization on a coupled heteronucleus. The RF pulse sequence developed by Goldman and co-workers [52] was employed (using the following delays: t 1 = 21 ms, t 2 = 37 ms, t 3 = 50 ms), Figure 4, but other pulse sequences can be also used [53–55, 57, 62, 68, 69]. After completion of this step, heteronuclear magnetization was detected with the parent spectrometer by applying a heteronuclear excitation pulse and turning on the receiver.…”

Section: Methodsmentioning

confidence: 99%

A pulse programmable parahydrogen polarizer using a tunable electromagnet and dual channel NMR spectrometer

Coffey

Shchepin

Feng

et al. 2017

Journal of Magnetic Resonance

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Applications of parahydrogen induced polarization (PHIP) often warrant conversion of the chemically-synthesized singlet-state spin order into net heteronuclear magnetization. In order to obtain optimal yields from the overall hyperpolarization process, catalytic hydrogenation must be tightly synchronized to subsequent radiofrequency (RF) transformations of spin order. Commercial NMR consoles are designed to synchronize applied waves on multiple channels and consequently are well-suited as controllers for these types of hyperpolarization experiments that require tight coordination of RF and non-RF events. Described here is a PHIP instrument interfaced to a portable NMR console operating with a static field electromagnet in the milliTesla regime. In addition to providing comprehensive control over chemistry and RF events, this setup condenses the PHIP protocol into a pulse-program that in turn can be readily shared in the manner of traditional pulse sequences. In this device, a TTL multiplexer was constructed to convert spectrometer TTL outputs into 24 VDC signals. These signals then activated solenoid valves to control chemical shuttling and reactivity in PHIP experiments. Consolidating these steps in a pulse-programming environment speeded calibration and improved quality assurance by enabling the B0/B1 fields to be tuned based on the direct acquisition of thermally polarized and hyperpolarized NMR signals. Performance was tested on the parahydrogen addition product of 2-hydroxyethyl propionate-1-13C-d3, where the 13C polarization was estimated to be P13C = 20 ± 2.5 % corresponding to 13C signal enhancement approximately 25 million-fold at 9.1 mT or approximately 77,000-fold 13C enhancement at 3 T with respect to thermally induced polarization at room temperature.

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On the spin order transfer from parahydrogen to another nucleus

Cited by 72 publications

References 30 publications

Liquid-state carbon-13 hyperpolarization generated in an MRI system for fast imaging

Liquid-state carbon-13 hyperpolarization generated in an MRI system for fast imaging

Parahydrogen‐Based Hyperpolarization for Biomedicine

A pulse programmable parahydrogen polarizer using a tunable electromagnet and dual channel NMR spectrometer

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