Hyperpolarised gas filling station for medical imaging using polarised 129Xe and 3He

Lee, Wai Tung; Zheng, Gang; Talbot, Cavin; Tong, Xin; D'Adam, Tim; Parnell, Steven R.; Veer, Michael de; Jenkin, Graham; Polglase, Graeme R.; Hooper, Stuart B.; Thompson, Bruce; Thien, Francis; Egan, Gary F.

doi:10.1016/j.mri.2021.02.010

Cited by 4 publications

(2 citation statements)

References 30 publications

(25 reference statements)

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“…Polarizers crucial for the production of HP gas can be custom built (28)(29)(30)(31)(32) or purchased from commercial companies such as Polarean and Xemed LLC (33, 34). Dedicated transceiver coils tuned to the resonance frequency of the gas nucleus of interest are also required.…”

Section: Hardwarementioning

confidence: 99%

Functional lung imaging using novel and emerging MRI techniques

et al. 2023

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Respiratory diseases are leading causes of death and disability in the world. While early diagnosis is key, this has proven difficult due to the lack of sensitive and non-invasive tools. Computed tomography is regarded as the gold standard for structural lung imaging but lacks functional information and involves significant radiation exposure. Lung magnetic resonance imaging (MRI) has historically been challenging due to its short T2 and low proton density. Hyperpolarised gas MRI is an emerging technique that is able to overcome these difficulties, permitting the functional and microstructural evaluation of the lung. Other novel imaging techniques such as fluorinated gas MRI, oxygen-enhanced MRI, Fourier decomposition MRI and phase-resolved functional lung imaging can also be used to interrogate lung function though they are currently at varying stages of development. This article provides a clinically focused review of these contrast and non-contrast MR imaging techniques and their current applications in lung disease.

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Section: Hardwarementioning

confidence: 99%

Functional lung imaging using novel and emerging MRI techniques

et al. 2023

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“…Polarization transfer from pH 2 to X-nuclei also attracts significant attention in the context of hyperpolarized MRI applications. The lack of background signal and extended lifetime of polarization (compared to 1 H) makes hyperpolarized MRI of X-nuclei highly interesting for biomedical applications, spearheaded by hyperpolarized MRI of xenon and 13 C-pyruvate [19,[47][48][49][50].…”

Section: Nuclear Spin Isomers Of H 2 and Ethylenementioning

confidence: 99%

Symmetry Constraints on Spin Order Transfer in Parahydrogen-Induced Polarization (PHIP)

et al. 2022

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It is well known that the association of parahydrogen (pH2) with an unsaturated molecule or a transient metalorganic complex can enhance the intensity of NMR signals; the effect is known as parahydrogen-induced polarization (PHIP). During recent decades, numerous methods were proposed for converting pH2-derived nuclear spin order to the observable magnetization of protons or other nuclei of interest, usually 13C or 15N. Here, we analyze the constraints imposed by the topological symmetry of the spin systems on the amplitude of transferred polarization. We find that in asymmetric systems, heteronuclei can be polarized to 100%. However, the amplitude drops to 75% in A2BX systems and further to 50% in A3B2X systems. The latter case is of primary importance for biological applications of PHIP using sidearm hydrogenation (PHIP-SAH). If the polarization is transferred to the same type of nuclei, i.e., 1H, symmetry constraints impose significant boundaries on the spin-order distribution. For AB, A2B, A3B, A2B2, AA’(AA’) systems, the maximum average polarization for each spin is 100%, 50%, 33.3%, 25%, and 0, respectively, (where A and B (or A’) came from pH2). Remarkably, if the polarization of all spins in a molecule is summed up, the total polarization grows asymptotically with ~1.27 and can exceed 2 in the absence of symmetry constraints (where is the number of spins). We also discuss the effect of dipole–dipole-induced pH2 spin-order distribution in heterogeneous catalysis or nematic liquid crystals. Practical examples from the literature illustrate our theoretical analysis.

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