Wideband method for signal amplification of magnetic resonance contrast agents within seconds and purification of magnetic resonance contrast agents - Patents.com

Abstract

The present invention relates to a method for transferring the two-spin order of a molecule (e.g. parahydrogen) upon hyperpolarization of at least one heteronucleus, comprising the steps of providing a molecule comprising two protons (e.g. parahydrogen pH2) and at least one heteronucleus S3, S4, the protons having nuclear spins coupled to the nuclear spins of the at least one heteronucleus, exposing the protons and the at least one heteronucleus to a for example uniform magnetic field (B0) in the z direction, which together with the x and y directions form a right-handed Cartesian coordinate system, and applying a sequence of radio frequency pulses to the protons and the at least one heteronucleus in order to transfer the two-spin order upon hyperpolarization of the at least one heteronucleus, the sequence of radio frequency pulses being selected from a first group N A , the second group N B , and the third group N C The first group N A The 180° high frequency pulse of is n during the first time interval τA. A The second group N B The 180° radio frequency pulses of n are generated during the second time interval after the last first group. B times in succession, the third group N C The 180° radio frequency pulses are placed after the last second group at a third time interval τ C Inside C n times in succession, A , n B , n C and applying, where each of the first and second inputs is an integer.

Description

[Technical field]

[0001] The present invention relates to a method for transferring spin order, for example of parahydrogen molecules, upon hyperpolarization of at least one heteronucleus. [Background technology]

[0002] Magnetic resonance imaging (MRI) is a technique widely used in research laboratories and clinics to examine and diagnose disease patterns.

[0003] However, a major drawback of MRI relates to the fact that the intensity of the nuclear magnetic resonance (NMR) signal depends on the difference between the nuclear spin state populations of the imaging nuclei. According to the Boltzmann equation (ΔN=γhB0 / (2πkT)), this difference is a function of temperature and the applied magnetic field, and at thermal equilibrium it is approximately equal to (10 -5 is relatively low (on the order of ).

[0004] To make diseases more visible, contrast agents that enhance the differences in water relaxation in various tissues are injected into the organism. Approximately 30 million examinations with contrast agents are performed annually in clinics around the world. Specialized forms of contrast agents that allow chemical processes such as metabolism to be directly observed are based on the process of hyperpolarization.

[0005] In the field of nuclear magnetic resonance (NMR), the hyperpolarization method, on which MRI is based, increases the signal of contrast agents by several orders of magnitude. Hyperpolarization is used, for example, to increase the signal of metabolites, which are then introduced to visualize metabolism in tumors. This has already been shown in human clinical trials. In particular, it has been shown that such methods can be used to identify tumors and evaluate the effectiveness of treatments.

[0006] A common method for amplifying signals by hyperpolarization is based on the dynamic nuclear polarization (DNP) technique. To achieve the greatest possible signal amplification, contrast agents are usually hyperpolarized at cryogenic temperatures (i.e., at temperatures below 2K) in the presence of radicals using microwave radiation. This process takes tens of minutes to hours and is therefore very time-consuming, which severely limits the use of this method. After signal amplification, the contrast agent is heated and dissolved so that it can be injected.

[0007] Another hyperpolarization method that delivers an amplified signal within seconds is based on parahydrogen or deuterium. The use of parahydrogen is the more common form of hyperpolarization. Parahydrogen is a spin isomer of hydrogen gas that is enriched by passing the corresponding gas through a catalyst (usually iron oxide or activated carbon) at low temperature. At 77 K, an enrichment of about 50% is achieved, and at 25 K, the enrichment is about 100%. Once the catalyst is removed after enrichment, the gas can be bottled and stored at room temperature for days to weeks ... 1x l 2x +l 1y l 2y +l 1z l 2z where x, y, and z are the axes of an orthogonal frame. The singlet spin order has two orthogonal components, namely the transverse two-spin order component ZQ x =l 1x l 2x +l 1y l 2y and the longitudinal two-spin order component l 1z l 2z where z is usually chosen as the direction of the applied magnetic field. In parahydrogen-based hyperpolarization processes, the spin order created by the concentration of parahydrogen is converted from the molecule into amplified signals, which are then used as contrast agents.

[0008] There are two modalities by which para-hydrogen can bind to a substrate to achieve a hyperpolarized signal. On the one hand, para-hydrogen can be added to a molecule by a catalyst, which changes the chemical structure of the substrate (para-hydrogen induced polarization (PHIP)). After the addition process, the spin order is converted into an amplified observable signal. On the other hand, para-hydrogen can form a transiently stable complex with a catalyst and a compound of interest (e.g., a metabolite) where the spin order is converted into an amplified signal of the compound of interest (the labile complex then dissociates again, yielding an unaltered signal-amplified imaging agent. This non-hydrogenated PHIP method is called SABRE (Signal Amplification By Reversible Exchange).

[0009] In both parahydrogen-based methods, the aim is to transfer maximum spin order of parahydrogen to the contrast agent. In principle, so-called heteronuclei, i.e. nuclei other than hydrogen, are to be hyperpolarized. This means that the heteronuclei in the contrast agent (e.g. 13 C and 15 N) can usually be followed for very long periods (minutes) even within living organisms. The most relevant is carbon-13( 13 C) isotope signal amplification, the reason for this is the carbon-13( 13 C) Isotopes are found in many metabolic products.

[0010] Several methods have already been developed to transfer spin order to these heteronuclei. They are based on the existence of couplings (J-couplings) between the individual spins involved, i.e. between the spin of parahydrogen, the spin of the nucleus to be hyperpolarized, and possibly other existing nuclei, that can be used for the transfer. In addition, it is involved that the individual nuclei in the molecule are observed at different spectroscopic frequencies (chemical shifts). These frequency differences can also be used for an efficient transfer.

[0011] Concerning the parahydrogen process (SABRE), where the contrast agent is not modified, the most efficient process is the magnetic field cycling method, where the spin order is converted into an amplified signal of the contrast agent at low magnetic fields. This technique involves the transfer of protons and 15 It works efficiently on N nuclei, but there are important 13 Does not produce medically relevant hyperpolarization of C compounds.

[0012] Addition of parahydrogen to unsaturated compounds (PHIP) and 13 Subsequent transfer to the C nucleus results in signal amplification up to an order of magnitude higher than SABRE. In recent years, unsaturated metabolite precursors have been developed, 13 The PHIP method, which allows the hyperpolarization of C nuclei and, after subsequent chemical transformation, their conversion into metabolic imaging agents, has become particularly relevant. A number of parahydrogen methods have already been developed, which can be used to: 13 It is possible to transfer spin order to C nuclei, especially contrast agents. However, in general, these methods are not effective enough to achieve high hyperpolarization values, which is why parahydrogen has not yet established itself as a widely available method. On the one hand, there is transfer by magnetic field circulation, which does not achieve strong signal amplification, and on the other hand, there are methods based on radio frequency (RF) pulses (RF methods).

[0013] RF methods can be classified based on the parahydrogen spin order that is converted into the heteronuclear signal: RF methods are based on couplings (J-couplings) that can be used to transfer between the individual spins involved, i.e., between the spin of parahydrogen, the spin of the nucleus to be hyperpolarized, and possibly the spins of other existing nuclei.

[0014] A subset of RF methods uses the resonance of proton spins at well-separated frequencies (chemical shifts), sometimes within a narrow frequency window compared to the frequency separation. In this way, the spins can be independently manipulated by selected RF pulses and / or the chemical shift differences can be effectively used for polarization transfer. These methods are unsuitable for use in low-field magnets, and compact, cost-effective systems usually have poor uniformity.

[0015] More than 90% of the spin order can theoretically be transferred by radio frequency pulses. However, the methods developed so far are not very robust or optimized for a specific J-coupling scheme. In particular, methods that try to maintain the singlet spin order of parahydrogen in PHIP or SABRE are mainly used. To ensure efficient transfer, very precise pulses must be used here, which is difficult to realize experimentally. Other methods use the so-called two-spin order or longitudinal order, which can arise when the parahydrogen used in PHIP or SABRE forms a complex in which the two nuclei are in a weakly coupled state. The weak coupling in PHIP occurs mainly, but not exclusively, at high magnetic fields (>0.5 Tesla). For this reason, 1. There is nothing to impede the polarization transfer except for the H nuclei with their associated parahydrogen or J-coupling to the heteronuclei, whose influence on the spin dynamics as discussed may be removed or ignored or refocused. 2. The chemical shift difference between the two nuclei is greater than the proton-proton J coupling, and / or 3. The J coupling difference for heteronuclei is larger than the HH J coupling It is necessary that the following applies.

[0016] Therefore, only experiments available for molecules with specific binding schemes, often limited to the use of high magnetic fields to achieve weak binding, can be designed for this approach.

[0017] After generating the hyperpolarization and preserving the contrast agent, it remains difficult to separate the necessary catalysts and place the contrast agent in aqueous solution to minimize health risks.

[0018] So far, the best process consists of a phase separation approach, where the contrast agent is produced in an organic (usually chlorinated) solvent and then extracted into the aqueous phase. However, this process depends on achieving optimal hyperpolarization results in a solvent that separates from water. In addition, when converting metabolite precursors to signal-amplifying metabolites, the reaction must also be fast enough in the organic solvent or at the interface during extraction. These two points are difficult to convert and limit the applications. [Prior art documents] [Non-patent literature]

[0019] [Non-Patent Document 1] "Pulsed Magnetic Resonance to Signal-Enhance Metaboliltes within Seconds by utilizing para-Hydrogen", ChemistryOpen 2018, 7,344-348, Sergey Korchak, Shengjun Yang, Salvatore Mamone, and Stefan Gloggler Summary of the Invention [Problem to be solved by the invention]

[0020] Based on the above, the problem underlying the present invention is to provide a rapid and efficient method for transferring the parahydrogen 2-spin order to heteronuclear hyperpolarization that can be applied to a variety of different contrast agents used in MRI. Furthermore, it is desirable to provide a method for purifying the hyperpolarized contrast agent, in particular to finally obtain an injection solution containing the hyperpolarized contrast agent. [Means for solving the problem]

[0021] The main object of the present invention is solved by a method comprising the features of claim 1. Preferred embodiments of this aspect of the invention are set out in the corresponding dependent claims and are explained below. Furthermore, other aspects of the invention are also detailed below.

[0022] According to claim 1, there is provided a method for transferring the 2-spin order of parahydrogen molecules to the hyperpolarization of at least one heteronucleus, comprising: Providing a molecule, particularly in the form of parahydrogen (pH2), and at least one heteronucleus, the molecule being in a pair of two protons of the molecule with a two-spin order, particularly a two-spin longitudinal order. 1z l 2z wherein the protons have a nuclear spin coupled to the nuclear spin of at least one heteronucleus; exposing the protons and the at least one hetero-nucleus to a magnetic field (B0) in a z direction (which may be a uniform magnetic field), the z direction forming a right-handed Cartesian coordinate system together with the x and y directions; applying a sequence of radio frequency pulses to the protons and the at least one heteronucleus to transfer the two-spin order to the hyperpolarization of the at least one heteronucleus, the sequence of radio frequency pulses comprising a first group, a second group and a third group of 180° radio frequency pulses, the first group of 180° radio frequency pulses being applied at a first time interval τ A Inside A times in succession, the second group of 180° radio frequency pulses is applied at a second time interval τ B Inside B times in succession, the third group of 180° radio frequency pulses is applied at a third time interval τ after the last second group. C Inside C n times in succession, A , n B , n C each of which is an integer; A method is disclosed that includes:

[0023] The spin order of a molecule (e.g., parahydrogen) can be transferred to various molecules, for example, by hydrogenation reactions or by the temporary association of parahydrogen and a substrate in transition metal-based catalysts (SABRE). The use of hydrogenated PHIP allows the parahydrogen spin orientation to be used very efficiently, since the two initial protons are part of the target molecule (e.g., the imaging agent), so that very high enhancement factors can be obtained. On the other hand, the SABRE approach does not require unsaturated precursors and allows the transfer of spin order by J-coupling, thus allowing the hyperpolarization of a different set of molecules without the need to use unsaturated precursors.

[0024] According to one embodiment, the magnetic field B0 is a homogeneous magnetic field, however, the method according to the invention also works in the case of inhomogeneous magnetic fields, especially when the RF pulse includes a bandwidth in which the dephasing due to diffusion is much larger than the dispersion introduced by homogeneity and is therefore insignificant.

[0025] According to a preferred embodiment of the method according to the invention, the first group of 180° high frequency pulses has a phase Ψ 11 and a first 180° radio frequency pulse acting on the protons, having a phase Ψ 21 and a preferably simultaneous second 180° radio frequency pulse acting on at least one heteronucleus, the first group of 180° radio frequency pulses preferably having a phase Ψ 12 and a third 180° radio frequency pulse acting on the protons, having a phase Ψ 22 and a preferably simultaneous fourth 180° radio frequency pulse impinging on at least one heteronucleus.

[0026] Preferably, all groups of 180° radio frequency pulses acting on the protons can be equally spaced in time, more particularly, all groups of 180° radio frequency pulses acting on at least one heteronucleus can be equally spaced in time.

[0027] According to a further embodiment of the invention, the second group of 180° high frequency pulses also have a phase Ψ 13 and a first 180° radio frequency pulse acting on the protons, having a phase Ψ 14 and a subsequent second 180° radio frequency pulse acting on the protons.

[0028] According to an alternative embodiment that can be used in the SABRE configuration, the second group of 180° radio frequency pulses has a phase Ψ 23 and a first 180° radio frequency pulse having a phase Ψ 13 and a subsequent second 180° radio frequency pulse acting on the protons, the second group of 180° radio frequency pulses having a phase Ψ 24 and a third 180° radio frequency pulse having a phase Ψ 14 and a subsequent fourth 180° radio frequency pulse acting on the protons, the third 180° radio frequency pulse and the fourth 180° radio frequency pulse of the second group being applied after the first group of 180° radio frequency pulses.

[0029] Furthermore, according to one embodiment of the present invention, the third group of 180° radio frequency pulses have a phase Ψ 15 and a first 180° radio frequency pulse acting on the protons, having a phase Ψ 25 and a second, preferably simultaneous, 180° radio frequency pulse acting on at least one heteronucleus, the third group of 180° radio frequency pulses having a phase Ψ 16 and a third 180° radio frequency pulse acting on the protons, having a phase Ψ 26 and a preferably simultaneous fourth 180° radio frequency pulse acting on at least one heteronucleus.

[0030] Furthermore, according to one embodiment, the first time interval τ A is the second time interval τ B and / or the first time interval τ A is the third time interval τ CAccording to a further embodiment, for every time interval τ A , τ B , τ C are different from each other.

[0031] Furthermore, according to a preferred embodiment of the method according to the invention, said integer n A , n B , n C is n A =1, n B = 1, and n C =1.

[0032] Furthermore, in accordance with a preferred embodiment, the integer n A , n B , n C is the triplet: A = 2, n B = 9, n C =5;n A =6, n B =3, n C =3;n A = 5, n B = 10, n C =1;n A =1, n B = 2, n C =11;n A =3, n B =1, n C =15;n A =11, n B =6, n C =15 can be selected.

[0033] Furthermore, according to a preferred embodiment, the first time interval τ A , the second time interval τ B , the third time interval τ C is the triplet: τ A = 135.1 ms, τ B = 71.1 ms, τ C = 135.1ms; τ A = 135.1 ms, τ B = 76.7 ms, τ C = 135.1ms; τ A = 1216 ms, τB =774ms、τ C =1486ms;t A =45.0ms、τ B =46.0ms、τ C =45.0ms;t A =45.0ms、τ B =45.2ms、τ C =45.0ms;t A =495ms、τ B =478ms、τ C =45ms;t A =3.0ms、τ B =44.3ms、τ C =3.0ms;τ A =3.0ms、τ B =44.8ms、τ C =3.0ms;τ A =1709ms、τ B =360ms、τ C =1709ms;t A =1709ms、τ B =504ms、τ C =1709ms;t A =2215ms、τ B =1521ms、τ C =2088ms;t A =135ms、τ B =73.9ms、τ C =58.1ms;t A =58.1ms、τ B =68.1ms、τ C =58.1ms;t A =174ms、τ B =657ms、τ C =58.1ms;t A =96.1ms、τ B =309.4ms、τ C =19.2ms;t A =19.2ms、τ B =1040ms、τ C =19.2ms;t A =19.2ms、τ B =787ms、τ C = 19.2ms out of 1つ can be selected.

[0034] In a further embodiment, each first time interval τ A Instead of the specific time values ​​given for each first time interval τ A can be in the range Ams to Bms, where A is τ A minus 25%, preferably minus 10%, more preferably minus 5%, and B is the value shown for τ A τ + 25%, preferably + 10%, more preferably + 5% (i.e., for example, τ A = 135.1 ms, according to a further embodiment, τ A may alternatively be in the range of 101.325 ms to 168.875 ms, preferably in the range of 121.59 ms to 148.61 ms, and more preferably in the range of 128.345 ms to 141.855 ms).

[0035] Similarly, the second time interval τ of each of the triplet B Instead of the specific time values ​​given for each second time interval τ B can be in the range of Cms to Dms, and C is τ B minus 25%, preferably minus 10%, more preferably minus 5%, and D is τ B plus 25%, preferably plus 10%, more preferably plus 5%.

[0036] Similarly, the third time interval τ of each of the triplet c Instead of the specific time values ​​presented for each third time interval τ c can be in the range Ems to Fms, and E is τ C minus 25%, preferably minus 10%, more preferably minus 5%, and F is the value shown for τ C plus 25%, preferably plus 10%, more preferably plus 5%.

[0037] Further specific examples are presented in Tables 1 to 3. In particular, the time interval τ A , τ B , τ C and an integer n A , n B , n C Suitable magnetic fields and heteronuclei for the above-mentioned embodiments relating to are presented below in Tables 1-3.

[0038] Furthermore, the phase Ψ of the 180° radio frequency pulse corresponds to the direction of each 180° radio frequency pulse in the coordinate system defined above in which the magnetic field B is aligned with the z direction (i.e., the direction in which the spins are flipped by 180° by each 180° radio frequency pulse). 11 , Ψ 12 , Ψ 13 , Ψ 14 , Ψ 15 , Ψ 16 , Ψ 21 , Ψ 22 , Ψ 25 , Ψ 26 Regarding the above, one embodiment of the present invention is to change the phase (e.g., Ψ 11 and Ψ 12 Similarly, in one embodiment, the phases (e.g., Ψ) of the 180° radio frequency pulses acting on at least one heteronucleus in each group are shifted by 180° with respect to each other. 21 and Ψ 22 etc.) are shifted by 180° relative to each other. According to a particular embodiment, the phase of the 180° radio frequency pulses acting on the protons can alternate between x and -x in each group. In the same way, the phase of the 180° radio frequency pulses acting on at least one heteronucleus can alternate between x and -x in each group.

[0039] According to a further embodiment,

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[0040] According to yet another embodiment of the method according to the invention, the sequence of radio frequency pulses has a phase φ 11 and further comprising a first 90° radio frequency pulse acting on the protons, the first group of 180° radio frequency pulses being spaced apart from the first 90° radio frequency pulse by a first time interval τ A Inside A times in succession, the sequence of radio frequency pulses has a phase φ 12 and further comprising a second 90° radio frequency pulse acting on the protons, the second 90° radio frequency pulse following the first 90° radio frequency pulse and having a first time interval τ A and a second group of 180° radio frequency pulses is applied to the protons at the end of the second time interval τ after the second 90° radio frequency pulse. B Inside B times in succession, the sequence of radio frequency pulses has a phase φ 13 and further comprising a third 90° radio frequency pulse acting on the protons, the third 90° radio frequency pulse following the second 90° radio frequency pulse and having a second time interval τ B and a third group of 180° radio frequency pulses is applied to the protons at the end of the third time interval τ after the third 90° radio frequency pulse.C N in C The voltage is applied successively.

[0041] In particular, the second 90° high frequency pulse is generated at a first time interval τ from the first 90° high frequency pulse. A The third 90° high frequency pulse is spaced a second time interval τ from the second 90° high frequency pulse. B The two are spaced apart by 100 mm.

[0042] According to a further embodiment, the sequence of radio frequency pulses has a phase φ 22 and a fourth 90° radio frequency pulse having a phase φ 23 and an optional subsequent fifth 90° radio frequency pulse acting on at least one heteronucleus, in particular the third 90° radio frequency pulse being simultaneous with said fourth 90° radio frequency pulse. Generally, in all embodiments the fifth radio frequency pulse can also be omitted. The subsequent pulses can therefore be renumbered accordingly.

[0043] In particular, the fifth 90° high frequency pulse is generated at a third time interval τ from the third 90° high frequency pulse and the fourth 90° high frequency pulse. C The two are spaced apart by 100 mm.

[0044] According to a preferred embodiment of the method according to the invention, the phase φ of the first 90° high frequency pulse 11 , the phase φ of the second 90° high frequency pulse 12 and the phase φ of the third 90° high frequency pulse 13 Furthermore, preferably, the phase φ of the fifth 90° high frequency pulse is 23 is the phase φ of the fourth 90° high frequency pulse 22 According to a particular embodiment, the individual phases are orthogonal to φ 11 =φ 12 =φ 13 = x, φ 22 = x, φ 23 = y, that is, the phase φ 11 , φ 12 , φ13 corresponds to the x direction and the phase φ 22 corresponds to the x direction and the phase φ 23 corresponds to the y direction.

[0045] Furthermore, in particular when hyperpolarization is achieved in the SABRE configuration, according to one embodiment of the invention, the sequence of radiofrequency pulses has a phase φ 14 and further comprising a sixth 90° radio frequency pulse acting on the protons, the sequence of radio frequency pulses having a phase φ 21 and further comprising a seventh 90° radio frequency pulse acting on at least one heteronucleus, in one embodiment the sixth 90° radio frequency pulse is simultaneous with the fifth 90° radio frequency pulse (if present), and in one embodiment the seventh 90° radio frequency pulse is simultaneous with the first 90° radio frequency pulse.

[0046] In particular, in this regard, according to one embodiment of the present invention, the phase φ of the first 90° high frequency pulse 11 , the phase φ of the second 90° high frequency pulse 12 , the phase φ of the third 90° high frequency pulse 13 and the phase φ of the sixth 90° high frequency pulse 14 are collinear and the phase φ of the seventh 90° high frequency pulse 21 is φ 21 =φ 23 +π. In a specific embodiment, the individual phases are 11 =φ 12 =φ 13 =φ 14 = x, φ 22 = x, φ 23 = y, and φ 21 =-y follows.

[0047] Furthermore, according to a preferred embodiment, the sequence of high frequency pulses is applied after the fifth 90° high frequency pulse and / or the sixth 90° high frequency pulse for a fourth time interval τ D In particular, the sequence of radio frequency pulses is repeated n times, n being an integer, preferably after the lapse of n A , nB , n C is n A =1, n B = 1, and n C =1.

[0048] According to a further embodiment of the method according to the invention, the step of providing a molecule (e.g., parahydrogen) and at least one heteronucleus also includes providing a further heteronucleus, the nuclear spin of the at least one heteronucleus being coupled to the nuclear spin of the further heteronucleus, the step of exposing the protons and the at least one heteronucleus to a uniform magnetic field B0 in the z direction also includes exposing the further heteronucleus to said magnetic field B0, and the step of applying a sequence of radio frequency pulses to the protons and the at least one heteronucleus to transfer said two-spin order to the hyperpolarization of the at least one heteronucleus also includes transferring the two-spin order to the hyperpolarization of the further heteronucleus.

[0049] According to one embodiment, the heteronucleus and the further heteronucleus can be of the same species (i.e., can be identical to each other), however, in one embodiment, the heteronucleus and the further heteronucleus can also be different from each other, i.e., belong to different species.

[0050] According to a further embodiment of the method, the sequence of radio frequency pulses (to achieve hyperpolarization of the two heteronuclei) has a phase φ 24 and a sixth radio frequency pulse of angle θ acting on the heteronuclei (i.e. the pulse inverts the respective spins by this angle θ) at a fourth time interval τ from the third 90° radio frequency pulse. D a sixth radio frequency pulse of angle θ spaced apart by a phase φ 25 and a seventh 90° radio frequency pulse acting on the heteronucleus, the seventh 90° radio frequency pulse being spaced apart from the sixth radio frequency pulse at an angle θ by a fifth time interval τ E In particular, in one embodiment, τ D and τE teeth,

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[0051] In particular, the efficiency for a heteronucleus (f1) and the efficiency for a further heteronucleus (f2) are given by f1=cos 2 θ, and f2=sin 2 θ, which can be used to determine the maximum efficiency when hyperpolarizing a heteronucleus or further heteronuclei (0° is cos 2 Maximize the term, and 90° is sin 2 (maximize the term). To distribute the polarization equally in both nuclei, a 45° pulse gives the best results. Therefore, according to one embodiment, θ=45°. However, other values ​​for θ are also conceivable.

[0052] According to a preferred embodiment of the method, the sequence of radio frequency pulses is in particular after said fifth 90° radio frequency pulse (if present) and in particular before said sixth radio frequency pulse of angle θ, with a phase Ψ 27 and acting on the heteronucleus, the sequence of said radio frequency pulses further comprising a 180° radio frequency pulse having a phase Ψ after a sixth radio frequency pulse of angle θ and before said seventh 90° radio frequency pulse. 28 and further includes a 180° radio frequency pulse acting on the heteronucleus.

[0053] In particular, in one embodiment, the phase of the two 180° radio frequency pulses is Ψ 22 =Ψ 28 = x and phase φ 24 =x and phase φ 25 =y.

[0054] The above-described methods of transferring spin order to at least one heteronucleus can be applied in a variety of different procedures to yield hyperpolarized (ie, signal-amplifying) imaging agents.

[0055] In particular, prior to the step of applying a sequence of radio frequency pulses to the protons and to the at least one heteronucleus in order to transfer the two-spin order to the hyperpolarization of the at least one heteronucleus, the molecule (e.g., parahydrogen pH2) is a transmitter which is not ultimately part of the hyperpolarized contrast agent (e.g. in SABRE the heteronucleus is temporarily bound to a catalyst, e.g. IR-Imes), in particular after transferring said two-spin order to the hyperpolarization of at least one heteronucleus, the intermediate state formed by the transmitter, said molecule (e.g. parahydrogen) and the molecule used as the contrast agent collapses or decomposes, releasing the hyperpolarized contrast agent, a precursor of a hyperpolarized contrast agent (e.g. phospho-enol-lactate), which is ultimately part of the hyperpolarized contrast agent, and at least one heteronucleus is constituted by the precursor, A precursor of a hyperpolarized contrast agent, which is then separated to obtain an imaging agent containing at least one heteronucleus (e.g. a metabolite such as pyruvate, acetate, lactate). In particular, the precursor can be a molecule containing a metabolite and an unsaturated double bond or an unsaturated triple bond. To such an unsaturated bond para hydrogen is added. Thus, after the hydrogenation step (i.e. addition of para hydrogen), the precursor can be, for example, ethyl acetate, ethyl lactate, ethyl pyruvate, cinnamyl acetate, cinnamyl lactate, cinnamyl pyruvate. A contrast agent, wherein at least one heteronucleus is constituted by a contrast agent. is added to one of the

[0056] Furthermore, in one embodiment of the method according to the invention, said at least one heteronucleus is contained in pyruvate. 13 C, contained in acetate 13C, contained in ethyl acetate 13 C, contained in cinnamyl acetate 13 C (1- of the cinnamyl moiety) 13 C) contained in cinnamyl acetate 13 C (2- of the cinnamyl moiety) 13 C) contained in lactate 13 C, contained in phosphoractate 31 P, contained in phospho-enol-lactate 13 C, contained in phospho-enol-lactate 31 P, contained in acetoacetic acid 13 C, contained in 3-hydroxybutyric acid 13 C, contained in amino acids 13 C, contained in fatty acids 13 C, contained in cinnamyl pyruvate 13 C, contained in cinnamyl lactate 13 One of the C's,

[0057] In particular, for phospho-enol-lactate, the two-spin order is 31 It can be moved to P, 13 C may also be involved (transfer of 2-spin order to two heteronuclei). In particular, the 2-spin order can be transferred from a proton to a heteronucleus and then to a further heteronucleus, which can be separately addressed by application of RF pulses. In particular, said transfer can be realized by intermediate spin states. In particular, this situation is not confined to cases where the heteronucleus and the further heteronucleus are the same species (e.g. 13 C) and separated or different by a large chemical shift (e.g., heteronuclei 31 Corresponding to P, further heteronuclei 13 C) is the case. In particular, in the case of phosphoractate, 31 P and 13 The intermediate spin state, which is the spin state between 13 It is needed to amplify the C signal.

[0058] According to a further embodiment of the method, said hyperpolarization of at least one heteronucleus is achieved in an organic solvent in the presence of a catalyst. Ideally, the solvent does not form an azeotrope with water but forms a phase. Such solvents are, for example, acetone and methanol.

[0059] According to a further embodiment of the method, after hyperpolarization of the at least one heteronucleus, the aqueous solution is added to the organic solvent.

[0060] Preferably, in one embodiment, the aqueous solution comprises a cleavage agent configured to cleave a precursor comprising at least one hyperpolarized heteronucleus to obtain a hyperpolarized contrast agent, in particular the precursor is a metabolite precursor and in particular the contrast agent is a metabolite contrast agent. Preferably, the cleavage agent is one of an acid, a base, an enzyme. In particular examples are basic hydrolysis with metal hydroxides (NaOH, KOH, CsOH, etc.), metal carbonates (NA2CO3, K2CO3, Cs2CO3, etc.), amines (trimethylamine, etc.), pyridine. A further example is acid hydrolysis with strong acids, in particular inorganic and organic acids, in particular trifluoroacetic acid, which can be removed by evaporation. According to yet another example, enzymes such as esterases (hydrolases) can be used.

[0061] According to a further embodiment of the method, a complexing agent is added to the organic solvent before or after the aqueous solution is added to the organic solvent to capture the catalyst. For example, dithizone, 1-(2-pyridylazo)-2-naphthol, etc., are soluble in the organic solvent. The complexing agent can be immobilized on microbeads for easier filtration. In particular, according to one embodiment, the complexing agent comprises microparticles having thiol groups that bind metals or other ligands.

[0062] According to a further embodiment of the method, the organic solvent is evaporated.

[0063] According to a further embodiment of the method, evaporation of the organic solvent is facilitated by applying a vacuum.

[0064] According to a further embodiment of the method, the evaporation of the organic solvent is driven by a stripping gas flow through the solution. The stripping gas can be any gas or vapor, preferably an inert gas, e.g., nitrogen, hydrogen. The stripping gas is more efficient when combined with a vacuum. The stripping gas can be added intentionally or can be the result of applying a vacuum in a setup where residual gas pressure (e.g., hydrogen) flows through the solution.

[0065] According to a further embodiment of the method, to obtain an injection solution containing the hyperpolarized contrast agent, the aqueous solution is filtered to remove at least one by-product precipitated upon evaporation (e.g. catalyst, side chain after cleavage, etc.) In particular, if the contrast agent is poorly soluble in water, an organic solvent is added to the injection solution, the organic solvent being, for example, ethanol.

[0066] According to an alternative embodiment of the method according to the invention, said hyperpolarization of at least one heteronucleus forming part of the contrast agent is achieved in a solvent, the solvent being one of an aqueous solution, an organic solution or a mixture of an aqueous and an organic solution.

[0067] Now, in one embodiment, the solvent is evaporated, leaving the hyperpolarised contrast agent, for example in solid form.

[0068] According to a further embodiment of the method, the contrast agent is washed with a solvent that the contrast agent does not dissolve in. In particular, the solvent can be one of chloroform, diethyl ether, heptane, a non-polar solvent.

[0069] Moreover, according to an embodiment of the method according to the invention, each radio frequency pulse is one of a rectangular pulse, a frequency selective pulse, and a shaped pulse having a shape deviating from a rectangular shape. In particular, a frequency selective pulse is a pulse that acts on only a few resonances (i.e., signals) of molecules and does not excite the entire spectrum. Furthermore, a shaped pulse deviates from a rectangular (i.e., hard) pulse. With a shaped pulse, not only can the excitation of resonances in the spectrum be enhanced, but also a better selectivity can be achieved during excitation. Thus, the shaped pulse also serves as a frequency selective pulse.

[0070] In one embodiment, in the sequence according to the invention, each pulse can be a rectangular pulse. However, instead of each rectangular pulse, a frequency-selective or shaped pulse can be used. In a further embodiment, in particular, each of the 180° high frequency pulses can be a frequency-selective or shaped pulse, while the remaining pulses can be, for example, rectangular pulses.

[0071] Moreover, according to one embodiment, the last radio frequency pulse for each heteronucleus in the sequences described herein can be used to tilt the magnetization along the z-axis, in particular to directly observe a fraction of the magnetization and to preserve the remainder of the magnetization, or to tilt the magnetization in any direction. Alternatively, this last pulse can be omitted in case of tilting the magnetization along the z-axis, allowing direct observation of all the magnetization.

[0072] In particular, the z-component can be referred to as the direction in which the magnetization is stored for later acquisition. If one only wants to acquire part of the signal and later the rest, one does not need to flip the entire magnetization in the z-direction.

[0073] The overall goal of each sequence specifically described herein is to produce magnetization, which is achieved at the end of the pulse sequence. The final 90° pulse brings the magnetization in the z direction for storage. If this pulse is not applied, then the signal can be observed directly.

[0074] Moreover, in one embodiment of the method, a contrast agent is added to a solution, such as a physiological buffer (eg, PBS or HEPES), to obtain an injection solution containing the contrast agent.

[0075] According to yet another aspect of the present invention there is disclosed a method for obtaining a hyperpolarised imaging agent, comprising the steps of: adding a molecule containing two protons that form a 2-spin order (e.g., parahydrogen) to a precursor of the hyperpolarized contrast agent; - isolating the precursor to obtain the contrast agent; - transferring the two spin orders to hyperpolarize at least one heteronucleus of the contrast agent so as to obtain a hyperpolarized contrast agent; Includes.

[0076] As mentioned above, it is not necessary to isolate the precursors, in particular the imaging agent can also be obtained directly after hydrogenation.

[0077] In particular, in one embodiment of this method, the transferring of 2-spin order to the hyperpolarization of at least one heteronucleus is carried out using a method according to the invention as described herein.

[0078] According to yet another aspect of the invention, there is provided a method for transferring the two-spin order of a molecule upon hyperpolarization of at least one heteronucleus (S3, S4), comprising the steps of: Providing a molecule comprising two protons (H1, H2) and at least one heteronucleus (S3, S4), the nuclear spins of the protons being coupled to the nuclear spins of the at least one heteronucleus (S3, S4), and the J-coupling between the protons and the at least one heteronucleus being greater than the J-coupling between the two protons (see, for example, Figures 1 and 5); transferring 2-spin order to at least one heteronucleus using a radio frequency pulse; A method is disclosed that includes:

[0079] In particular, the protons and at least one heteronucleus can be exposed to a (e.g., static) magnetic field (B0) (e.g., in the z-direction). Alternatively, other than the radiofrequency pulse, the heteronucleus and the protons may also not be exposed to a separate (e.g., static) magnetic field at all. That is, the method according to this aspect of the invention can be used / performed without regard to the magnetic field.

[0080] Generally, the present invention allows optimal application of a pulse delivery method independent of the external magnetic field, especially when a longitudinal or two-spin order can be generated (see also above). This is usually achieved almost exclusively in high magnetic fields. However, this spin state is also achieved in low magnetic fields if the initial conditions indicated above are fulfilled, i.e. the J-coupling between the proton and at least one heteronucleus is greater than the J-coupling between the two protons. The pulse sequences presented herein are specific illustrations of this aspect of the invention. A specific implementation of the pulse sequence according to the invention is described, for example, for the molecule cinnamyl acetate (2) in Tables 2 and 3, showing that the conditions of the pulse sequence are independent of the magnetic field. Moreover, the above-mentioned further aspects of the invention, as claimed in claim 18, can be further specified by the individual features and examples of the method according to the invention disclosed herein.

[0081] According to yet another aspect of the present invention, there is provided a method for obtaining an injection solution containing a contrast agent, comprising the steps of: The hyperpolarization of the at least one heteronucleus is carried out in an organic solvent with the aid of a catalyst, after the hyperpolarization of the at least one heteronucleus an aqueous solution is added to the organic solvent, the aqueous solution may comprise a cleavage agent configured to cleave the precursor comprising the hyperpolarized at least one heteronucleus to obtain the hyperpolarized contrast agent, a complexing agent may be added to the organic solvent before or after the aqueous solution is added to the organic solvent in order to capture the catalyst, the organic solvent may be evaporated or removed by a stripping gas, the aqueous solution may be filtered to remove by-products and / or impurities precipitated upon evaporation in order to obtain an injection solution comprising the contrast agent, or A method is disclosed in which the hyperpolarization of at least one heteronucleus forming part of the contrast agent is carried out in a solvent, the solvent being one of an aqueous solution, an organic solution or a mixture of an aqueous and an organic solution, the solvent being evaporated or removed by using a stripping gas leaving the hyperpolarized contrast agent in particular in solid form, the contrast agent being washed with a solvent in which the contrast agent is insoluble and the contrast agent being added to the solution to obtain an injection solution containing the contrast agent.

[0082] In particular, the methods can be further defined based on the features and examples of the various hyperpolarization methods described herein.

[0083] Further embodiments, features and advantages of the present invention are described below with reference to the drawings. [Brief description of the drawings]

[0084] [Figure 1] The nuclear spin network with associated bonds is shown: J12: J bond between the two protons of parahydrogen, δHH: chemical shift between the two protons, J13: bond between one proton and the heteronucleus S3, and J23: bond between the other proton and the heteronucleus S3. [Diagram 2] FIG. 1 shows a diagram of one embodiment of a method according to the invention for efficient polarization transfer, comprising three (particularly different) time intervals τA, τB and τC and three repeatable groups (also denoted as blocks) NA, NB and NC of 180° pulses. [Diagram 3] 1 shows the transfer efficiency of the method according to the invention in terms of binding and time interval τ A in the strongly non-equivalent regime. [Figure 4] A depiction of the broadband transfer efficiency (left) and an example for the fixed time in the strongly non-equivalent regime are shown. [Diagram 5] An example of the method using an extended spin system with additional heteronuclei is given. [Figure 6] The pulse sequence for transferring spin order to two heteronuclei as shown in Figure 5 is shown below. The key is the pulse with angle Θ, which allows us to separate the spin order between multiple heteronuclei (e.g., S3 and S4 in Figure 5). [Figure 7] An example of a sequence applied for SABRE is shown, where τD is a delay allowing the release of the substrate bound to the H2-catalyst complex at the end of the sequence. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0085] As shown in Figure 2, the present invention provides an efficient broadband method that can be used to amplify a large number of contrast agents within seconds. Advantageously, the method can be used for both PHIP and SABRE. The method uses the robust 2-spin order created by the protons H1, H2 of the parahydrogen pH2 (see Figure 1), but achieves high efficiency (>90%) even when there is only a small difference (>0.1 Hz) between the individual J-couplings. Radio frequency pulses are used to efficiently convert this order into hyperpolarization of the heteronuclear spins. An exemplary NMR pulse sequence to achieve this spin order transfer is shown in Figure 2.

[0086] In particular, according to one embodiment (see Figs. 1 and 2), the method comprises the steps of providing a molecular system such as parahydrogen (pH2) containing two protons and at least one heteronucleus S3, the protons H1 and H2 (see Fig. 1) having nuclear spins coupled to the nuclear spins of the at least one heteronucleus S3 (parahydrogen can be added to the precursor or transmitter involved in the preparation of the contrast agent in various ways as further explained below), exposing the protons and the at least one heteronucleus to a magnetic field B0 in the z direction (in particular the magnetic field B0 can be a uniform magnetic field), which together with the x and y directions form a right-handed Cartesian coordinate system, and applying a sequence of radio frequency (RF) pulses to the protons H1 and H2 and the at least one heteronucleus S3 in order to transfer the two-spin order to hyperpolarization of the at least one heteronucleus S3, the sequence of radio frequency pulses being arranged in three repeatable groups (also denoted as blocks) N A , N B , N C 180° RF pulse at integer n A , n B , n C and applying a first time interval τ A is the first group N A Similarly, the second time interval τ B and a third time interval τ c is the second group N B and the third group N C These durations are shown below.

[0087] In particular, the example in Figure 2 shows A =n B =n C = 1 and τ A = τ C Corresponds to.

[0088] First group N A and the third group N C are protons, 1 In the H channel, the phase Ψ11 , Ψ 12 and Ψ 15 , Ψ 16 Two 180° radio frequency pulses P1, P3 and P7, P9, in the heteronuclear S channel, with phase Ψ 21 , Ψ 22 and Ψ 25 , Ψ 26 The pulses P1 and P2, P3 and P4, P7 and P8, P10 have the same wavelength, and the pulses P1 and P3 are simultaneous, the pulses P7 and P8, and the pulses P9 and P10 are simultaneous. However, the respective synchronicities are not strict, and the pulse pairs P1 and P2, P3 and P4, P7 and P8, and P9 and P10 may be separated in time by a certain time interval. It is suggested that the evolution caused by the chemical shift, J coupling and RF offset may be 1 The time separation between the pulses in the H and S channels is negligible. In particular, the time interval between the preferred simultaneous RF pulses (e.g., P1 and P2, P3 and P4, P7 and P8, and P9 and P10) is less than 100 ms, particularly less than 10 ms, and especially less than 1 ms.

[0089] In particular, the second group N B simply comprises two subsequent 180° pulses P5, P6 with phases Ψ13, Ψ14 in the proton channel.

[0090] Furthermore, a sequence of radio frequency pulses acts successively on the proton channel, with a phase φ 11 A first 90° radio frequency pulse RF1 having a phase φ 12 a second 90° radio frequency pulse RF2 having a phase φ 13 and a third 90° radio frequency pulse RF3 having a phase φ 22 and a 90° radio frequency pulse RF4 having a phase φ 23 and a 90° radio frequency pulse RF5 having a

[0091] As shown in Figure 2, each group N A , N B , N C The 180° pulses are applied between the subsequent 90° pulses RF1, RF2; RF2, RF3 / RF4; RF3 / RF4, RF5.

[0092] In particular, a 90° radio frequency pulse RF3 is applied to the protons H1, H2 at the same time T3 as the above-mentioned 90° radio frequency pulse RF4 is applied to the at least one heteronucleus S3. Furthermore, in particular, the 90° pulses in the two channels are separated by the above-mentioned time interval τ A , τ B , and τ C Additionally, as shown in FIG. 2, the second 180° pulses P3, P4, P6, P9, P10 of each of the last repetitions of each group immediately precede the subsequent 90° pulses RF2, RF3 / RF4, RF5.

[0093] In particular, each group N immediately before the subsequent 90° pulses RF2, RF3 / RF4, and RF5 A , N B , N C These 180° pulses P3, P4, P6, P9, P10 of the last repetition are omitted in one embodiment and the phase of the 90° RF pulses is adjusted accordingly.

[0094] Further, optionally, a second group N B is the phase Ψ in the heteronuclear channel. 23 and Ψ 24 These optional RF pulses P11, P12 can also be present in other embodiments of the method according to the invention (see Figs. 6 and 7). At low magnetic fields, these optional 180° RF pulses P11, P12 can help to increase the efficiency of the sequence when conditions are towards proton equivalence.

[0095] The particular selection of the phase of the individual RF pulses, which corresponds to the direction of the respective RF pulse with respect to a coordinate system whose z-direction is aligned with the magnetic field B0, can be, for example, Phase φ of the first 90° radio frequency pulse RF1 11 , the phase φ of the second 90° radio frequency pulse RF2 12 , and the phase φ of the third 90° radio frequency pulse RF3 13 are all collinear, Phase φ of the fifth 90° radio frequency pulse RF5 23 is the phase φ of the fourth 90° radio frequency pulse RF4. 22 perpendicular to This is shown by:

[0096] In a particular embodiment, φ 11 =φ 12 =φ 13 = x, φ 22 = x, φ 23 = y, i.e. the first 90° RF pulse RF1, the second 90° RF pulse RF2, the third 90° RF pulse RF3 are in the x direction, the fourth 90° RF pulse is in the x direction, and the fifth 90° RF pulse is in the y direction.

[0097] Furthermore, the phase of the 180° pulses in each channel of each group may be shifted relative to one another by 180°. In particular, the phase of the 180° pulses in each channel of each group may alternate between x and −x.

[0098] In particular, in one embodiment, the phase of the 180° RF pulse is Ψ 11 =Ψ 13 =Ψ 13 = x, Ψ 12 =Ψ 14 =Ψ 16 = -x, Ψ 21 =Ψ 25 = x, and Ψ 22 =Ψ 26 In particular, when the 180° RF pulses P11 and P12 are present, Ψ 23 =Ψ 21 and Ψ 24 =Ψ 26can be selected.

[0099] In general, three processes for obtaining the desired contrast agent can be recognized that can take advantage of the above-mentioned transfer mechanisms: 1) Para-hydrogen is added to a mediator that is not ultimately part of the signal amplification molecule. This mediator is either an unsaturated bond of a contrast agent precursor (PHIP) or a metal complex that is only temporarily stable (SABRE). Spin order is then transferred from para-hydrogen to the heteronucleus in the desired compound. The temporarily stable molecule is then destroyed or the precursor is decomposed to yield the desired contrast agent. 2) Parahydrogen is added to the imaging agent precursor (or imaging agent), which is finally part of the imaging agent. Spin order is also transferred to the heteronucleus to generate an amplified signal. Here, for example, protecting groups can be used to stabilize the unsaturated precursor for hydrogenation. These are then separated to give the imaging agent. 3) Parahydrogen is added to the precursor, which is then separated to obtain the contrast agent. Only after separation is the spin order transferred to the heteronucleus. This process is particularly useful when the proton polarization after addition has a long life. Furthermore, this process can be useful to create a bond network that is more favorable for transfer.

[0100] Each of the general procedures listed under subsections 1)-3) greatly benefits from the robust and efficient broadband spin order transfer methodology of the present invention.

[0101] More particularly, the method according to the invention can be used in one of at least three scenarios: A) All spins considered are weakly coupled (all chemical shifts are larger than the J coupling) as a prerequisite for the creation of two-spin order. Hereafter, this is called the high-field example. B) The hydrogenation reaction is carried out in a high magnetic field under the conditions mentioned in A), and for the transfer attempt, where these conditions do not apply, it is brought to a lower magnetic field B0. It is still possible to produce the desired polarization of the heteronuclei by the method according to the invention. This is hereinafter referred to as the low magnetic field example. C) The method can be used independently of a magnetic field when the proton-heteronuclear bond is much larger than all other bonds, in particular at least three times larger, in particular at least five times larger, in particular at least ten times larger.

[0102] High magnetic field example In the high magnetic field example, n A =n B =n C = 1 and τ A = τ C is preferably used according to one embodiment. WC To evaluate |, the following shorthand is introduced: Δ J =||J 13 |-|J 23 || Σ J =|J 13 |+|J 23 |

[0103] These relations allow the various time intervals τ A , τ B , τ C It is possible to select the optimal transfer conditions for the transfer efficiency.

[0104] For a simplified representation, Figure 4 shows a one-dimensional projection of the efficiency and possible parameter paths according to Figure 3.

[0105] In particular, the efficiency figures show that the method can be used broadband and therefore exceeds the prior art.

[0106] The example given above in C) and more specifically the same sequence of FIG. 2 can be used for very large proton-heteronuclear bonds.

[0107] Tables 1, 2 and 3 below provide examples of related molecules and their optimized parameters. The most related molecules are pyruvate, acetate and lactate, as well as other carboxylic acids, all of which have similar bond networks.

[0108] In particular, in the table below, ethyl acetate and cinnamyl acetate each form a precursor to the contrast agent, while the phosphoractate corresponds to the contrast agent.

[0109] [Table 1]

[0110] [Table 2]

[0111] [Table 3]

[0112] Low magnetic field example In example B) above, the highest possible efficiency is n A , n B and n C , and time τ A , τ B and τ C are considered respectively with respect to each other and optimized with respect to coupling, this is achieved with the illustrated pulse sequence in Figure 2.

[0113] Multiple heteronuclear signal amplifier In addition to amplifying the signal of only one heteronucleus, it may be useful to hyperpolarize several heteronuclei, for example to observe different metabolic pathways. This is also possible by extending the sequence shown in Figure 2. The considered spin system is shown in Figure 5 and extended by another heteronucleus S4. This allows for a different chemical shift δ between the two heteronuclei. SS and J 34An extension of the above sequence is shown in Figure 6.

[0114] According to this, the sequence of radio frequency pulses used to achieve the transfer of spin order is 24 (for example, this pulse can be in the x-direction) and acting on the heteronuclear S channel, D The sequence further includes radio frequency pulses RF8 of angle θ spaced apart by a phase φ 25 (e.g., in the y direction) and includes a further 90° radio frequency pulse RF9 acting on the heteronuclear S channel, the further 90° radio frequency pulse RF9 being at a fifth time interval τ from the above radio frequency pulse RF8 at an angle θ. E The two are spaced apart by 100 mm.

[0115] In particular, τ D and τ E teeth,

number

number

[0116] Furthermore, after the 90° radio frequency pulse RF5 and before the radio frequency pulse RF7 with the angle θ, 27 Another 180° radio frequency pulse P13 (for example in the x direction) is applied in the heteronuclear channel S. Furthermore, after the high frequency RF7 of angle θ and before the 90° radio frequency pulse RF9, a phase Ψ 28 A 180° radio frequency pulse P14 having a polarization (eg, in the x direction) is applied in the heteronuclear S channel.

[0117] Further, for the sequence of FIG. 6, which represents the transitions to S3 and S4, beginning at time T4: 1 H decoupling can be added and RF pulses P13, RF8 and P14 can be replaced by a single continuous wave (CW) irradiation containing much more power than the chemical shift difference between S3 and S4 to adjust the polarization for S3 and S4.

[0118] Furthermore, the sequence according to FIG. 6 also includes a second group N B But in the heteronuclear channel, the phase Ψ 23 and Ψ 24 It may include optional further 180° RF pulses P11, P12 having

[0119] Moreover, according to yet another modification of the sequence shown in FIG. 6, the radio frequency pulse RF5 can be omitted.

[0120] Moreover, Figure 7 shows a further embodiment of the method according to the invention, which relates to a SABRE sequence. In particular, SABRE refers to the PHIP method in which a para-hydrogen molecule, a catalyst and a substrate (as well as other supporting co-ligands, including a solvent) come together to form a labile complex. The complex persists long enough for transfer polarization from the para-hydrogen to the target heteronucleus of the substrate. The substrate is then released in a chemically unmodified form, leaving the catalyst ready for another transfer cycle, if the hydrogen molecule is also released.

[0121] For hydrogenation PHIP, there are two ways to transfer parahydrogen order to the target heteronuclei in SABRE: the first involves passing the sample through different magnetic fields (field cycling method), and the second utilizes radio frequency pulses and delays in one fixed magnetic field (RF method).

[0122] With appropriate modifications, known ESOTHERIC pulse sequences (see "Pulsed Magnetic Resonance to Signal-Enhance Metabolites within Seconds by utilizing para-Hydrogen", ChemistryOpen 2018, 7,344-348, by Sergey Korchak, Shengjun Yang, Salvatore Mamone, and Stefan Gloggler) can be adapted to transfer the spin order in PHIP-SABRE. In the SABRE polarization transfer, the existence of two substrate pools must be considered: one in which the substrate is bound to the catalyst-H2 complex, and the other in which the substrate is free.

[0123] below, There are no nuclear spins directly coupled to the heteronucleus, except for H2 in the bound hydrogen-catalyst-substrate, which may require deuteration of the substrate; or In the presence of protons directly bonded to the heteronucleus, the protons can be selectively decoupled or refocused by appropriate choice of timing of the induced generation; It is expected.

[0124] Compared to the original ESOTHERIC, the changes are particularly as follows: H2-catalyst-substrate complex is formed, sequence

number

number

number

[0125] For each cycle in the loop, the maximum spin order I 1Z I 2Z It is important that H2-catalyst-substrate complexes are present. This can be achieved by introducing a bubble-up period at the beginning of the loop cycle or by continuous bubble-up of para-H2.

[0126] In this simplified model, the maximum polarization achievable in a free substrate is

number

number

[0127] In particular, as shown in FIG. 7, the sequence includes three groups of 180° RF pulses, the first group NA contains 180° RF pulses P1, P3 in the proton channel and 180° RF pulses P2, P4 in the heteronuclear channel, where pulses P1, P3, P2, P4 have phases Ψ 11 , Ψ 12 , Ψ 21 , Ψ 22 Furthermore, the second group N B contains 180° RF pulses P5, P6 in the proton channel and 180° RF pulses P11, P12 in the heteronuclear channel, where pulses P5, P6, P11, P12 have phase Ψ 13 , Ψ 14 , Ψ 23 , Ψ 24 Furthermore, the third group N C contains 180° RF pulses P7, P9 in the proton channel and 180° RF pulses P8, P10 in the heteronuclear channel, where pulses P7, P9, P8, P10 have phase Ψ 15 , Ψ 16 , Ψ 25 , Ψ 26 has.

[0128] In each group, the 180° RF pulse is A , the second time interval τ B and a third time interval τ C Specifically, as one illustrative example, each time interval may be 3 seconds or less.

[0129] In particular, the fourth time interval τ D is a delay allowing the release of the substrate bound to the H2-catalyst complex at the end of the sequence. In a particular embodiment of the sequence, the following values ​​for the phase (direction) of the RF pulse can be chosen: For each sub-block, the phase of two 180° pulses in the same channel is shifted by 180 degrees relative to each other. The phase of the 90° pulse in the 1H channel (φ 11 , φ 12 , φ 13 , φ 14 ) are collinear. Phase φ 22can be freely selected. Phase φ 23 is φ 22 is perpendicular to Phase φ 21 =φ 23 +π. A specific choice is all phases in each subblock, alternating between x and -x, φ 11 =φ 12 =φ 13 =φ 14 = x, φ 22 = x, φ 23 = y, φ 21 =-y.

[0130] In another practical embodiment of the sequence, any 180° pulse preceding a 90° pulse can be dropped by appropriate adjustment of the phase of the subsequent 90° pulse.

[0131] Similarly, optionally, a second group N B is the phase Ψ in the heteronuclear channel. 23 and Ψ 24 The further 180° RF pulses P11, P12 having

[0132] In particular, when the 180° RF pulses P11 and P12 are present, Ψ 23 =Ψ 21 and Ψ 24 =Ψ 26 can be selected.

[0133] Contrast agent purification Reactions for signal amplification and processing of contrast agents can be conducted according to the examples described below.

[0134] In particular, hyperpolarization is achieved by a catalyst in an organic solvent. Ideally, the solvent does not form an azeotrope with water but a phase. Such solvents are, for example, acetone and methanol. After heteronuclear signal amplification (for example as described herein), an aqueous solution is added to the reaction mixture. The aqueous solution may contain substrates (for example acids or bases or enzymes) that decompose the metabolite precursors to obtain signal-amplified metabolites. In addition, a complexing agent may be added to the solution to capture the catalyst used. Complexing agents are, for example, microparticles with thiol groups that bind poorly soluble metals or other ligands in a complex. This step can be performed already in advance before the addition of water to the organic solvent. The organic solvent is then evaporated, evaporation can also mean the removal of the solvent by a stripping gas. Evaporation can be promoted by applying a vacuum, with or without a stripping gas. The stripping gas can be added intentionally or can be the result of a residual pressure of a gas (for example hydrogen) in the setup after applying the vacuum.

[0135] During this process, by-products and impurities (catalyst, side chain after decomposition, etc.) may precipitate, which are then removed by filtering the aqueous solution. Finally, a pure injection solution with a contrast agent is obtained. For contrast agents that are poorly soluble in water, an organic solvent, for example in the form of ethanol, can be added to the injection solution.

[0136] Alternatively, the contrast agent can be hyperpolarized in an aqueous or organic solution or mixture thereof. The solvent is then evaporated, leaving the contrast agent. The contrast agent can then be washed with a solvent in which it is insoluble. Absorption of the contrast agent in the solution results in a pure injectable solution.

[0137] According to a specific example (particularly in the context of PHIP), a 0.5 ml solution of 100 mM phenylacetylene pyruvate and 2 mM rhodium catalyst in acetone-d6 is hydrogenated at 50C with 7 bars of p-H2 to obtain cinnamyl pyruvate. The pressure is released. 0.1 ml of 10 mM chelating agent (dithizone or another insoluble in water) is added to the acetone solution. 0.5 ml of 100 mM sodium carbonate in water is added to hydrolyze the precursor in 2 seconds, freeing pyruvate and cinnamyl alcohol. The acetone is evaporated under vacuum (residual hydrogen gas flows through the solution, mixing with it and thus promoting evaporation) and 0.2 ml concentrated PBS buffer is added. The solution is filtered to remove cinnamyl alcohol, complexed rhodium and insoluble catalyst residues, leaving pure pyruvate in physiological PBS buffer.

[0138] Moreover, according to yet another specific example (in the context of SABRE), a 0.5 ml solution of 100 mM 15N nicotinic acid and 2 mM iridium catalyst in methanol d3 is hydrogenated at 30 C with 7 bars p-H2 for 20 seconds. The pressure is released. 0.1 ml of 10 mM chelating agent (dithizone or another insoluble in water) is added to the methanol solution. 0.5 ml of biological PBS buffer is added. The methanol is evaporated under vacuum. The solution is filtered to remove the complexed iridium and insoluble catalyst residues, leaving pure nicotinic acid in physiological PBS buffer.

[0139] Moreover, according to one embodiment, in all sequences described herein or shown in Figures 2, 6 and 7, the last radio frequency pulse on the hetero-nuclei is used to tilt the magnetization along the z-axis. In principle, this radio frequency pulse can be of any value if one wishes to directly observe a portion of the magnetization and preserve the rest of the magnetization. This radio frequency pulse can be omitted if one wishes to directly observe all of the magnetization.

[0140] The present invention further includes, but is not limited to, the following items. Each item can therefore also be explicitly stated as a claim of this application, which can be related to other claims as set forth in the dependent claims set forth in the item. The reference numbers stated in parentheses refer to the above figures.

[0141] Item 1: A method for transferring molecular 2-spin order upon hyperpolarization of at least one heteronucleus, comprising: Providing a molecule containing two protons and at least one heteronucleus (S3, S4), the protons having a nuclear spin coupled to the nuclear spin of the at least one heteronucleus; exposing the protons and the at least one hetero-nucleus to a magnetic field (B0) in a z direction, the z direction forming a right-handed Cartesian coordinate system with the x and y directions; applying a sequence of radio frequency pulses to the protons and to the at least one heteronucleus in order to transfer the two-spin order to the hyperpolarization of the at least one heteronucleus, the sequence of radio frequency pulses being a first group (N A ), the second group (N B ), and the third group (N C ) 180° high frequency pulses, A ) 180° high frequency pulses are generated during the first time interval (τA) A times in succession, B ) after the last of the first group, a second time interval (τ B ) in n B times in succession, C ) after the last second group, a 180° radio frequency pulse is generated at a third time interval (τ C ) in n C n times in succession, A , n B , n C each of which is an integer; A method comprising:

[0142] Item 2: The first group (N A ) 180° high frequency pulse has phase Ψ 11 and a first 180° radio frequency pulse (P1) acting on the protons, the first 180° radio frequency pulse having a phase Ψ 21 and a second 180° radio frequency pulse (P2) acting on said at least one heteronucleus (S3), and said first group (N A ) 180° high frequency pulse has phase Ψ 12 and a third 180° radio frequency pulse (P3) acting on the protons and having a phase Ψ 22 and a fourth 180° radiofrequency pulse (P4) acting on said at least one heteronucleus (S3).

[0143] Item 3: The second group (N B ) 180° high frequency pulse has phase Ψ 13 and a first 180° radio frequency pulse (P5) acting on the protons, having a phase Ψ 14 and a subsequent second 180° radio frequency pulse (P6) acting on the protons.

[0144] Item 4: The second group (N B ) 180° high frequency pulse has phase Ψ 23 and a first 180° radio frequency pulse (P11) acting on said at least one heteronucleus (S3), having a phase Ψ 13 and a subsequent second 180° radio frequency pulse (P5) acting on the protons, B ) 180° high frequency pulse has phase Ψ 24 and a third 180° radiofrequency pulse (P12) acting on said at least one heteronucleus (S3), having a phase Ψ 14 and a subsequent fourth 180° radio frequency pulse (P6) acting on the protons, B The third 180° high frequency pulse (P12) and the fourth 180° high frequency pulse (P6) of the second group (N B3. The method according to claim 1 or 2, wherein said first 180° high frequency pulse (P5) is applied after said second 180° high frequency pulse (P6).

[0145] Item 5: The third group (N C ) 180° high frequency pulse has phase Ψ 15 and a first 180° radio frequency pulse (P7) acting on the protons, having a phase Ψ 25 and a second 180° radio frequency pulse (P8) acting on said at least one heteronucleus (S3), and said third group (N C ) 180° high frequency pulse has phase Ψ 16 and a third 180° radio frequency pulse (P9) acting on the protons, having a phase Ψ 26 and a fourth 180° radiofrequency pulse (P10) acting on said at least one heteronucleus (S3).

[0146] Item 6: The first time interval (τ A ) is the second time interval (τ B ), and / or the first time interval (τ A ) is the third time interval (τ C 6. The method according to any one of items 1 to 5, wherein the method is equivalent to

[0147] Item 7: The integer n A , n B , n C is n A =1, n B = 1, and n C 7. The method according to any one of items 1 to 6, wherein the compound is selected so that =1.

[0148] Item 8: Each group (N A , N B , N C ), the phases of the 180° radio frequency pulses acting on the protons are shifted by 180° relative to each other, and / or each group (N A , N B , N C8. The method according to any one of claims 1 to 7, wherein the phases of the 180° radiofrequency pulses acting on the at least one heteronucleus are shifted by 180° relative to each other.

[0149] Item 9: Said n A The first group (N A ), the third 180° high frequency pulse (P3) and the fourth high frequency pulse (P4) are omitted, and / or the n B The second group (N B ), the second 180° high frequency pulse (P6) or the fourth 180° high frequency pulse (P6) is omitted, and / or the n C The third group (N C 9. The method according to any one of items 1 to 8, wherein the third 180° radiofrequency pulse (P9) and the fourth radiofrequency pulse (P10) are omitted.

[0150] Item 10: The sequence of high frequency pulses has a phase φ 11 and further comprising a first 90° radio frequency pulse (RF1) acting on the protons, and the first group (N A ) is a 180° radio frequency pulse that is generated at the first time interval (τ A ) in n A times in succession, the sequence of radio frequency pulses having a phase φ 12 and further comprising a second 90° radio frequency pulse (RF2) acting on the protons, the second 90° radio frequency pulse (RF2) following the first 90° radio frequency pulse (RF1) and having a first time interval (τ A ) is applied to the protons at the end of the second group (N B ) after the second 90° radio frequency pulse (RF2), the second time interval (τ B ) in n B times in succession, the sequence of radio frequency pulses having a phase φ 13and further comprising a third 90° radio frequency pulse (RF3) acting on the protons, the third 90° radio frequency pulse (RF3) following the second 90° radio frequency pulse (RF2) and having a second time interval (τ B ) is applied to the protons at the end of the third group (N C ) after the third 90° radio frequency pulse (RF3), the third time interval (τ C ) in n C 10. The method according to any one of items 1 to 9, wherein the first and second voltages are applied successively.

[0151] Item 11: The sequence of high frequency pulses has a phase φ 22 and a fourth 90° radio frequency pulse (RF4) having a phase φ 23 and a subsequent optional fifth 90° radio frequency pulse (RF5) acting on said at least one heteronucleus, in particular said third 90° radio frequency pulse (RF3) being simultaneous with said fourth 90° radio frequency pulse (R4).

[0152] Item 12: The phase φ of the first 90° radio frequency pulse (RF1) 11 , the phase φ of the second 90° radio frequency pulse (RF2) 12 , and the phase φ of the third 90° radio frequency pulse (RF3) 13 are collinear, and / or the phase (φ 23 ) is the phase (φ 22 ), and in particular, φ 11 =φ 12 =φ 13 = x, φ 22 = x, φ 23 12. The method according to item 10 or 11, wherein:

[0153] Item 13: The sequence of high frequency pulses has a phase φ 14and a sixth 90° radio frequency pulse (RF6) acting on the protons, the sequence of radio frequency pulses having a phase φ 21 and further comprising a seventh 90° radio frequency pulse (RF7) acting on said at least one heteronucleus (S3), in particular said sixth 90° radio frequency pulse (RF6) being simultaneous with said fifth 90° radio frequency pulse (RF5), in particular said seventh 90° radio frequency pulse (RF7) being simultaneous with said first 90° radio frequency pulse (RF1).

[0154] Item 14: The phase φ of the first 90° radio frequency pulse (RF1) 11 , the phase φ of the second 90° radio frequency pulse (RF2) 12 , the phase φ of the third 90° radio frequency pulse (RF3) 13 , and the phase φ of the sixth 90° radio frequency pulse (RF6) 14 are collinear, and the phase φ of the seventh 90° radio frequency pulse (RF7) 21 is φ 21 =φ 23 +π, in particular, φ 11 =φ 12 =φ 13 =φ 14 = x, φ 22 = x, φ 23 = y, and φ 21 Item 14. The method according to item 13, wherein:

[0155] Item 15: The sequence of radio frequency pulses includes a fourth time interval (τ 1 ) after applying the fifth 90° radio frequency pulse (RF5) and / or the sixth 90° radio frequency pulse (RF6). D 15. The method according to claim 13, wherein the sequence of radiofrequency pulses is repeated after a lapse of n times, n being an integer.

[0156] Item 16: The method according to any one of items 1 to 12, wherein the step of preparing a molecule and at least one heteronucleus also includes preparing a further heteronucleus (S4), wherein the nuclear spin of the at least one heteronucleus (S3) is coupled to the nuclear spin of the further heteronucleus (S4), and the step of exposing the protons and the at least one heteronucleus to a magnetic field (B0) in the z direction also includes exposing the further heteronucleus (S4) to the magnetic field (B0), and the step of applying a sequence of radio frequency pulses to the protons and the at least one heteronucleus (S3) to transfer the two-spin order to the hyperpolarization of the at least one heteronucleus (S3) also includes transferring the two-spin order to the hyperpolarization of the further heteronucleus (S4).

[0157] Item 17: The method according to claim 16, wherein the heteronucleus and the further heteronucleus can be of the same species or can belong to different species.

[0158] Item 18: The sequence of high frequency pulses has a phase φ 24 and a sixth radio frequency pulse (RF8) having an angle θ and acting on the heteronuclei (S3, S4), the sixth radio frequency pulse (RF8) having a fourth time interval (τ D ) at an angle θ, and the sequence of radio frequency pulses further includes a sixth radio frequency pulse (RF8) having a phase φ 25 and a seventh 90° radio frequency pulse (RF9) acting on the heteronuclei (S3, S4), the seventh 90° radio frequency pulse (RF9) being at a fifth time interval (τ E 18. The method according to claim 16 or 17, wherein the first and second electrodes are spaced apart by at least one of the first and second electrodes.

[0159] Item 19: The sequence of radio frequency pulses is in particular arranged to have a phase Ψ after the fifth 90° radio frequency pulse (RF5) and / or before the sixth radio frequency pulse (RF8) with an angle θ. 27and acting on said heteronuclei (S3, S4), said sequence of radio frequency pulses further comprising a 180° radio frequency pulse (P13) having a phase Ψ after said sixth radio frequency pulse (RF8) of angle θ and before said seventh 90° radio frequency pulse (RF9). 28 19. The method according to items 11 and 18, further comprising a 180° radiofrequency pulse (P14) acting on said heteronuclei (S3, S4).

[0160] Item 20: The method according to item 16, wherein the sequence of radiofrequency pulses further comprises a single continuous wave irradiation acting on the two heteronuclei (S3, S4), the single continuous wave irradiation comprising a power greater than the chemical shift difference between the two heteronuclei (S3, S4) so ​​as to adjust the polarization of the two heteronuclei (S3, S4).

[0161] Item 21: To obtain a hyperpolarized contrast agent comprising at least one heteronucleus (S3), prior to the step of applying a sequence of radio frequency pulses to the protons and to the at least one heteronucleus in order to transfer the two-spin order to the hyperpolarization of the at least one heteronucleus (S3), the molecule is a transmitter that is not ultimately part of said hyperpolarised contrast agent; a precursor of said hyperpolarized contrast agent, which precursor is ultimately part of said hyperpolarized contrast agent, said at least one heteronucleus (S3) being constituted by said precursor, a precursor of said hyperpolarised contrast agent, which is subsequently separated to obtain said contrast agent comprising said at least one heteronucleus (S3), An imaging agent, wherein said at least one heteronucleus is constituted by said imaging agent. 21. The method according to any one of items 1 to 20, further comprising adding one of the following:

[0162] Item 22: The at least one heteronuclear group (S3, S4) is Contained in pyruvate 13 C. Contained in acetate 13 C. Contained in ethyl acetate 13 C. Contained in cinnamyl acetate 13 C(1), Contained in cinnamyl acetate 13 C(2), Included in lactate 13 C. Contained in phosphoractate 31 P, Contained in phospho-enol-lactate 13 C. Contained in phospho-enol-lactate 31 P, Contained in acetoacetic acid 13 C. Contained in 3-hydroxybutyric acid 13 C. Contained in amino acids 13 C. Contained in fatty acids 13 C. Contained in cinnamyl pyruvate 13 C. Contains cinnamyl lactate 13 C 22. The method according to any one of items 1 to 21, wherein the method is one of the following:

[0163] Item 23: The method according to any one of items 1 to 22, wherein each of the high-frequency pulses is one of a rectangular pulse, a frequency-selective pulse, and a shaped pulse having a shape deviating from a rectangular shape.

[0164] Item 24: The final radio frequency pulse for the heteronucleus is In particular, it can be used to tilt the magnetization along the z-axis in order to directly observe a portion of the magnetization and to preserve the remainder of the magnetization, or it can be used to tilt the magnetization in any direction. This is omitted when tilting the magnetization along the z-axis to allow direct observation of all of the magnetization. 24. The method according to any one of items 1 to 23, wherein

[0165] Item 25: A method for transferring the two-spin order of a molecule upon hyperpolarization of at least one heteronucleus (S3, S4), comprising: Providing a molecule comprising two protons (H1, H2) and said at least one heteronucleus (S3, S4), said protons being coupled by their nuclear spins to the nuclear spins of said at least one heteronucleus (S3, S4), and a J-coupling between one proton and said at least one heteronucleus being greater than the J-coupling between two of said protons; transferring said 2-spin order to said at least one heteronucleus using a radio frequency pulse; A method comprising:

[0166] Item 26: The method according to any one of items 1 to 25, wherein the hyperpolarization of the at least one heteronucleus is carried out in an organic solvent with the aid of a catalyst.

[0167] Item 27: The method of item 26, wherein after the hyperpolarization of the at least one heteronucleus, an aqueous solution is added to the organic solvent.

[0168] Item 28: The method of item 27, wherein the aqueous solution comprises a cleavage agent configured to cleave the hyperpolarized precursor comprising the at least one heteronucleus to obtain a hyperpolarized imaging agent.

[0169] Item 29: The method according to any one of items 26 to 28, wherein a complexing agent is added to the organic solvent before or after adding the aqueous solution to the organic solvent to sequester the catalyst.

[0170] Item 30: The method according to item 29, wherein the organic solvent is evaporated or removed by using a stripping gas. In particular, the evaporation of the organic solvent is assisted by applying a vacuum. In particular, the evaporation of the organic solvent is assisted by a stripping gas flow through the aqueous solution. The stripping gas can be any gas or vapor, preferably an inert gas, e.g. nitrogen, hydrogen.

[0171] Item 31: The method according to Item 30, wherein the aqueous solution is filtered to remove by-products and / or impurities precipitated upon evaporation to obtain an injection solution containing the contrast agent.

[0172] Item 32: The method according to any one of items 1 to 25, wherein the hyperpolarization of the at least one heteronucleus forming part of the contrast agent is carried out in a solvent, the solvent being one of an aqueous solution, an organic solution, or a mixture of an aqueous and an organic solution.

[0173] Item 33: The method according to item 32, wherein the solvent is evaporated or removed by using a stripping gas, leaving the hyperpolarized contrast agent, particularly in solid form. In particular, the evaporation of the organic solvent is induced by applying a vacuum. In particular, the evaporation of the organic solvent is induced by a stripping gas flow through the solution. The stripping gas can be any gas or vapor, preferably an inert gas, e.g. nitrogen, hydrogen.

[0174] Item 34: The method of item 33, wherein the contrast agent is washed with a solvent in which the contrast agent is insoluble.

[0175] Item 35: The method according to item 34, wherein the contrast agent is added to a solution to obtain an injection solution containing the contrast agent.

[0176] Item 36: A method for obtaining a hyperpolarized contrast agent, comprising: adding a molecule containing two protons that form a 2-spin order to a precursor of the contrast agent; separating said precursor to obtain said contrast agent; - transferring said two spin orders to hyperpolarize at least one heteronucleus of said contrast agent to obtain said hyperpolarized contrast agent; A method comprising:

[0177] Item 37: The method according to item 36, wherein the hyperpolarization of the at least one heteronucleus to transfer the two spin orders is carried out using the method according to any one of items 1 to 20, 22 to 35.

[0178] Item 38: A method for obtaining an injection solution containing a contrast agent, comprising the steps of: the hyperpolarization of the at least one heteronucleus is carried out with the aid of a catalyst in an organic solvent, after said hyperpolarization of the at least one heteronucleus an aqueous solution is added to the organic solvent, the aqueous solution may contain a cleavage agent configured to cleave a precursor comprising the hyperpolarized at least one heteronucleus to obtain a hyperpolarized contrast agent, a complexing agent may be added to the organic solvent before or after adding the aqueous solution to the organic solvent in order to capture the catalyst, the organic solvent is evaporated or removed by using a stripping gas, the aqueous solution is filtered to remove by-products and / or impurities precipitated during evaporation in order to obtain an injection solution comprising the contrast agent, or A method, wherein hyperpolarization of at least one heteronucleus forming part of a contrast agent is carried out in a solvent, said solvent being one of an aqueous solution, an organic solution or a mixture of an aqueous solution and an organic solution, said solvent being evaporated or removed by using a stripping gas, leaving said hyperpolarized contrast agent in particular in solid form, said contrast agent being washed with a solvent in which said contrast agent is insoluble, said contrast agent being added to the solution to obtain an injection solution containing said contrast agent.

[0179] Item 39: The method according to claim 38, wherein the evaporation of the organic solvent is induced by applying a vacuum, in particular the evaporation of the organic solvent is induced by a stripping gas flow through the solution.

Claims

1. At least one heteronuclear (S ３ , S ４ ), a method for transferring molecular 2-spin order to hyperpolarized Two protons (H １ , H ２ ) and said at least one heteronucleus (S ３ , S ４ ), wherein the protons have a nuclear spin that is closer to the at least one heteronucleus (S ３ , S ４ ) coupled to the nuclear spins of The magnetic field in the z direction (B ０ ), wherein the z direction forms a right-handed Cartesian coordinate system with the x and y directions; to transfer the two-spin order to the hyperpolarization of the at least one heteronucleus (S ３ , S ４ ), wherein the sequence of radio frequency pulses is Ａ ), the second group (N Ｂ ), and the third group (N Ｃ ) 180° high frequency pulses, Ａ ) 180° high frequency pulses are generated during the first time interval (τA) Ａ are applied successively times, and the second group (N Ｂ ) after the last of the first group, a 180° radio frequency pulse is generated at a second time interval (τ Ｂ ) in Ｂ times in succession, and the third group (N Ｃ ) after the last of the second group, a 180° radio frequency pulse is generated at a third time interval (τ Ｃ ) in Ｃ is applied n times in succession, Ａ , n Ｂ , n Ｃ each being an integer; A method comprising:

2. The first group (N Ａ ) 180° high frequency pulse of phase Ψ １１ a first 180° radio frequency pulse (P1) acting on the protons and having a phase Ψ ２１ and said at least one heteronucleus (S ３ ) and a second 180° high frequency pulse (P2) acting on the first group (N Ａ ) 180° high frequency pulse of phase Ψ １２ and a third 180° radio frequency pulse (P3) acting on the protons and having a phase Ψ ２２ and said at least one heteronucleus (S ３ and a fourth 180° high frequency pulse (P4) acting on the first and second 180° high frequency pulses (P1, P2, P3, P4).

3. The second group (N Ｂ ) 180° high frequency pulse of phase Ψ １３ and a first 180° radio frequency pulse (P5) acting on the protons and having a phase Ψ １４ and a subsequent second 180° radio frequency pulse (P6) having a first 180° frequency and acting on the protons.

4. The second group (N Ｂ ) 180° high frequency pulse of phase Ψ ２３ and said at least one heteronucleus (S ３ ) and a first 180° high frequency pulse (P11) acting on the １３ and a subsequent second 180° radio frequency pulse (P5) acting on the protons, Ｂ ) 180° high frequency pulse of phase Ψ ２４ and said at least one heteronucleus (S ３ ) and a third 180° high frequency pulse (P12) acting on the １４ and a subsequent fourth 180° radio frequency pulse (P6) acting on the protons, Ｂ The third 180° high frequency pulse (P12) and the fourth 180° high frequency pulse (P6) of the second group (N Ｂ 2. The method of claim 1, wherein the second 180° radio frequency pulse (P5) is applied after the second 180° radio frequency pulse (P6).

5. The third group (N Ｃ ) 180° high frequency pulse of phase Ψ １５ and a first 180° radio frequency pulse (P7) acting on the protons and having a phase Ψ ２５ and said at least one heteronucleus (S ３ ) and a second 180° high frequency pulse (P8) acting on the third group (N Ｃ ) 180° high frequency pulse of phase Ψ １６ and a third 180° radio frequency pulse (P9) acting on the protons and having a phase Ψ ２６ and said at least one heteronucleus (S ３ and a fourth 180° high frequency pulse (P10) acting on the first and second 180° high frequency pulses (P11).

6. The sequence of radio frequency pulses has a phase φ １１ and further comprising a first 90° radio frequency pulse (RF1) acting on said protons, said first group (N Ａ ) after the first 90° radio frequency pulse (RF1), the first time interval (τ Ａ ) in Ａ times in succession, the sequence of radio frequency pulses having a phase φ １２ and acting on the protons, the second 90° radio frequency pulse (RF2) following the first 90° radio frequency pulse (RF1) and the first time interval (τ Ａ ) is applied to the protons at the end of the second group (N Ｂ ) after the second 90° radio frequency pulse (RF2), the second time interval (τ Ｂ ) in Ｂ times in succession, the sequence of radio frequency pulses having a phase φ １３ and acting on the protons, the third 90° radio frequency pulse (RF3) following the second 90° radio frequency pulse (RF2) and the second time interval (τ Ｂ ) is applied to the protons at the end of the third group (N Ｃ ) after the third 90° radio frequency pulse (RF3), the third time interval (τ Ｃ ) in Ｃ The method of claim 1 , wherein the voltage is applied twice in succession.

7. The sequence of radio frequency pulses has a phase φ ２２ and said at least one heteronucleus (S ３ ) and a fourth 90° radio frequency pulse (RF4) acting on the ２３ and said at least one heteronucleus (S ３ 7. The method according to claim 6, further comprising a subsequent fifth 90° radio frequency pulse (RF5) acting on the third 90° radio frequency pulse (RF3) and the fourth 90° radio frequency pulse (RF4), in particular the third 90° radio frequency pulse (RF3) being simultaneous with the fourth 90° radio frequency pulse (RF4).

8. The phase φ of the first 90° radio frequency pulse (RF1) １１ , the phase φ of the second 90° radio frequency pulse (RF2) １２ , and the phase φ of the third 90° radio frequency pulse (RF3) １３ are collinear, and / or the phase (φ ２３ ) is the phase (φ) of the fourth 90° radio frequency pulse (RF4). ２２ ), and in particular, φ １１ =φ １２ =φ １３ = x, φ ２２ = x, φ ２３ 7. The method of claim 6, wherein y=y.

9. The sequence of radio frequency pulses has a phase φ １４ and acting on said protons, said sequence of radio frequency pulses further comprising a sixth 90° radio frequency pulse (RF6) having a phase φ ２１ and said at least one heteronucleus (S ３ 8. The method of claim 7, further comprising a seventh 90° radio frequency pulse (RF7) acting on the first 90° radio frequency pulse (RF1), wherein in particular the sixth 90° radio frequency pulse (RF6) is simultaneous with the fifth 90° radio frequency pulse (RF5), and in particular the seventh 90° radio frequency pulse (RF7) is simultaneous with the first 90° radio frequency pulse (RF1).

10. The phase φ of the first 90° radio frequency pulse (RF1) １１ , the phase φ of the second 90° radio frequency pulse (RF2) １２ , the phase φ of the third 90° radio frequency pulse (RF3) １３ , and the phase φ of the sixth 90° radio frequency pulse (RF6) １４ are collinear, and the phase φ of the seventh 90° radio frequency pulse (RF7) ２１ is φ ２１ =φ ２３ +π, and in particular, φ １１ =φ １２ =φ １３ =φ １４ = x, φ ２２ = x, φ ２３ = y, and φ ２１ 10. The method of claim 9, wherein: = -y.

11. The step of providing a molecule and at least one heteronucleus may also include providing a further heteronucleus (S ４ ) wherein said at least one heteronucleus (S ３ ) is such that the nuclear spin of the further heteronucleus (S ４ ) coupled to the nuclear spins of the magnetic field (B ０ The step of exposing the protons and the at least one heteronucleus to the magnetic field (B ０ ) to the further heteronuclear (S ４ ), wherein the at least one heteronucleus (S ３ ) to transfer the two-spin order to the hyperpolarization of the proton and the at least one heteronucleus (S ３ ) also comprises applying a sequence of radio frequency pulses to the further heteronucleus (S ４ 8. The method of claim 7, comprising transferring the two-spin order to hyperpolarization of the heteronucleus.

12. The sequence of radio frequency pulses has a phase φ ２４ and the heteronucleus (S ３ , S ４ ) at a fourth time interval (τ ) from the third 90° radio frequency pulse (RF3). Ｄ ) and the sequence of radio frequency pulses further includes a sixth radio frequency pulse (RF8) of an angle θ spaced apart by a phase φ ２５ and the heteronucleus (S ３ , S ４ ) and the seventh 90° radio frequency pulse (RF9) acts on the fifth time interval (τ ) from the sixth radio frequency pulse (RF8) at an angle θ. Ｅ 12. The method of claim 11 , wherein the first and second electrodes are spaced apart by at least one of the distances 1 to 120 mm.

13. The sequence of radio frequency pulses includes a pulse having a phase Ψ after the fifth 90° radio frequency pulse (RF5) and before the sixth radio frequency pulse (RF8) at an angle θ. ２７ and the heteronucleus (S ３ , S ４ ), the sequence of radio frequency pulses further comprising a 180° radio frequency pulse (P13) acting on the axial direction of the sine wave ... ２８ and the heteronucleus (S ３ , S ４ 13. The method of claim 12, further comprising a 180° radio frequency pulse (P14) acting on the

14. The sequence of radio frequency pulses is ３ , S ４ ) and in particular two of said heteronuclei (S ３ , S ４ ) to adjust the polarization relative to the two heteronuclei (S ３ , S ４ 12. The method of claim 11, further comprising a single continuous wave irradiation comprising a power greater than the chemical shift difference between the two.

15. The at least one heteronuclear group (S ３ ) to obtain a hyperpolarized imaging agent comprising said at least one heteronuclear (S ３ ), the molecule is subjected to a sequence of radio frequency pulses to transfer the 2-spin order to the hyperpolarization of a transmitter that is not ultimately part of said hyperpolarized contrast agent; a precursor of said hyperpolarized contrast agent, said precursor being ultimately part of said hyperpolarized contrast agent, said at least one heteronuclear (S ３ ) is a precursor of the hyperpolarized contrast agent, which is constituted by said precursor, a precursor of said hyperpolarized contrast agent, which is then converted to said at least one heteronuclear (S ３ a precursor of said hyperpolarised contrast agent, which is separated to obtain said contrast agent comprising an imaging agent, wherein said at least one heteronucleus is constituted by said imaging agent; The method of claim 1 , wherein the hydroxybenzoate is added to one of the following:

16. 10. The method of claim 1, wherein each of the radio frequency pulses is one of a rectangular pulse, a frequency selective pulse, and a shaped pulse having a shape deviating from a rectangular shape.

17. The final radio frequency pulse for the heteronucleus is In particular, it can be used to tilt the magnetization along the z-axis in order to directly observe a portion of the magnetization and preserve the remainder of the magnetization, or it can be used to tilt the magnetization in any direction. It is omitted when tilting the magnetization along the z-axis to allow direct observation of all of the magnetization. The method of claim 1 , wherein the method is one of:

18. At least one heteronuclear (S ３ , S ４ ), a method for transferring molecular 2-spin order to hyperpolarized Two protons (H １ , H ２ ) and said at least one heteronucleus (S ３ , S ４ ), wherein the protons have a nuclear spin that is closer to the at least one heteronucleus (S ３ , S ４ ) wherein the J coupling between one proton and said at least one heteronucleus is greater than the J coupling between two of said protons; transferring said 2-spin order to said at least one heteronucleus using a radio frequency pulse; A method comprising:

19. the hyperpolarization of the at least one heteronucleus is carried out in an organic solvent with the aid of a catalyst; after the hyperpolarization of the at least one heteronucleus, an aqueous solution is added to the organic solvent, which may contain a cleavage agent configured to cleave a precursor comprising the hyperpolarized at least one heteronucleus to obtain a hyperpolarized contrast agent; a complexing agent may be added to the organic solvent before or after adding the aqueous solution to the organic solvent in order to capture the catalyst; the organic solvent is evaporated or removed by using a stripping gas; and the aqueous solution is filtered to remove by-products and / or impurities precipitated during evaporation to obtain an injectable solution comprising the contrast agent; or 2. The method of claim 1, wherein the hyperpolarization of the at least one heteronucleus forming part of the contrast agent is carried out in a solvent, the solvent being one of an aqueous solution, an organic solution, a mixture of an aqueous solution and an organic solution, the solvent being evaporated or removed by using a stripping gas, leaving the hyperpolarized contrast agent, in particular in solid form, the contrast agent being washed with a solvent in which it is insoluble, and the contrast agent being added to the solution to obtain an injection solution containing the contrast agent.

20. 1. A method for obtaining an injection solution containing a contrast agent, comprising: the hyperpolarization of at least one heteronucleus is carried out in an organic solvent with the aid of a catalyst, after said hyperpolarization of said at least one heteronucleus an aqueous solution is added to said organic solvent, said aqueous solution may contain a cleavage agent configured to cleave a precursor comprising said hyperpolarized at least one heteronucleus to obtain a hyperpolarized contrast agent, a complexing agent may be added to said organic solvent before or after adding said aqueous solution to said organic solvent in order to capture said catalyst, said organic solvent is evaporated or removed by using a stripping gas, and said aqueous solution is filtered to remove by-products and / or impurities precipitated during evaporation in order to obtain an injectable solution comprising said contrast agent, or 1. A method according to claim 1, wherein the hyperpolarization of at least one heteronucleus forming part of a contrast agent is carried out in a solvent, said solvent being one of an aqueous solution, an organic solution, a mixture of an aqueous solution and an organic solution, said solvent being evaporated or removed by using a stripping gas, leaving said hyperpolarized contrast agent, in particular in solid form, said contrast agent being washed with a solvent in which said contrast agent is insoluble, said contrast agent being added to the solution in order to obtain an injection solution containing said contrast agent.

21. 21. The method according to claim 19 or 20, wherein the evaporation of the organic solvent is induced by applying a vacuum, in particular the evaporation of the organic solvent is induced by a stripping gas flow through the solution.

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