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Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses

Hyperpolarized MRI with (13)C‐labeled metabolites has enabled metabolic imaging of tumors in vivo. The heterogeneous nature of tumors and the limited lifetime of the hyperpolarization require high resolution, both temporally and spatially. We describe two sequences that make more efficient use of th...

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Autores principales: Wang, Jiazheng, Hesketh, Richard L., Wright, Alan J., Brindle, Kevin M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220795/
https://www.ncbi.nlm.nih.gov/pubmed/30198124
http://dx.doi.org/10.1002/nbm.4004
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author Wang, Jiazheng
Hesketh, Richard L.
Wright, Alan J.
Brindle, Kevin M.
author_facet Wang, Jiazheng
Hesketh, Richard L.
Wright, Alan J.
Brindle, Kevin M.
author_sort Wang, Jiazheng
collection PubMed
description Hyperpolarized MRI with (13)C‐labeled metabolites has enabled metabolic imaging of tumors in vivo. The heterogeneous nature of tumors and the limited lifetime of the hyperpolarization require high resolution, both temporally and spatially. We describe two sequences that make more efficient use of the (13)C polarization than previously described single‐shot 3D sequences. With these sequences, the target metabolite resonances were excited using spectral‐spatial pulses and the data acquired using spiral readouts from a series of echoes created using a fast‐spin‐echo sequence employing adiabatic 180° pulses. The third dimension was encoded with blipped gradients applied in an interleaved order to the echo train. Adiabatic inversion pulses applied in the absence of slice selection gradients allowed acquisition of signal from odd echoes, formed by unpaired adiabatic pulses, as well as from even echoes. The sequences were tested on tumor‐bearing mice following intravenous injection of hyperpolarized [1‐(13)C]pyruvate. [1‐(13)C] pyruvate and [1‐(13)C] lactate images were acquired in vivo with a 4 × 4 × 2 cm(3) field of view and a 32 × 32 × 16 matrix, leading to a nominal resolution of 1.25 × 1.25 × 1.25 mm(3) and an effective resolution of 1.25 × 1.25 × 4.5 mm(3) when the z‐direction point spread function was taken into account. The acquisition of signal from more echoes also allowed for an improvement in the signal‐to‐noise ratio for resonances with longer T (2) relaxation times. The pulse sequences described here produced hyperpolarized (13)C images with improved resolution and signal‐to‐noise ratio when compared with similar sequences described previously.
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spelling pubmed-62207952018-11-13 Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses Wang, Jiazheng Hesketh, Richard L. Wright, Alan J. Brindle, Kevin M. NMR Biomed Research Articles Hyperpolarized MRI with (13)C‐labeled metabolites has enabled metabolic imaging of tumors in vivo. The heterogeneous nature of tumors and the limited lifetime of the hyperpolarization require high resolution, both temporally and spatially. We describe two sequences that make more efficient use of the (13)C polarization than previously described single‐shot 3D sequences. With these sequences, the target metabolite resonances were excited using spectral‐spatial pulses and the data acquired using spiral readouts from a series of echoes created using a fast‐spin‐echo sequence employing adiabatic 180° pulses. The third dimension was encoded with blipped gradients applied in an interleaved order to the echo train. Adiabatic inversion pulses applied in the absence of slice selection gradients allowed acquisition of signal from odd echoes, formed by unpaired adiabatic pulses, as well as from even echoes. The sequences were tested on tumor‐bearing mice following intravenous injection of hyperpolarized [1‐(13)C]pyruvate. [1‐(13)C] pyruvate and [1‐(13)C] lactate images were acquired in vivo with a 4 × 4 × 2 cm(3) field of view and a 32 × 32 × 16 matrix, leading to a nominal resolution of 1.25 × 1.25 × 1.25 mm(3) and an effective resolution of 1.25 × 1.25 × 4.5 mm(3) when the z‐direction point spread function was taken into account. The acquisition of signal from more echoes also allowed for an improvement in the signal‐to‐noise ratio for resonances with longer T (2) relaxation times. The pulse sequences described here produced hyperpolarized (13)C images with improved resolution and signal‐to‐noise ratio when compared with similar sequences described previously. John Wiley and Sons Inc. 2018-09-10 2018-11 /pmc/articles/PMC6220795/ /pubmed/30198124 http://dx.doi.org/10.1002/nbm.4004 Text en © 2018 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Articles
Wang, Jiazheng
Hesketh, Richard L.
Wright, Alan J.
Brindle, Kevin M.
Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
title Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
title_full Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
title_fullStr Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
title_full_unstemmed Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
title_short Hyperpolarized (13)C spectroscopic imaging using single‐shot 3D sequences with unpaired adiabatic refocusing pulses
title_sort hyperpolarized (13)c spectroscopic imaging using single‐shot 3d sequences with unpaired adiabatic refocusing pulses
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220795/
https://www.ncbi.nlm.nih.gov/pubmed/30198124
http://dx.doi.org/10.1002/nbm.4004
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