Development of a Symmetric Echo-Planar Spectroscopy Imaging Framework for Hyperpolarized 13C Imaging in a Clinical PET/MR Scanner

Abubakr Eldirdiri, Stefan Posse, Lars G. Hanson, Rie Beck Hansen, Pernille Holst, Christina Schøier, Annemarie T Kristensen, Helle Hjorth Johannesen, Andreas Kjær, Adam E Hansen, Jan Henrik Ardenkjær-Larsen*

*Corresponding author for this work

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Abstract

Here, we developed a symmetric echo-planar spectroscopic imaging (EPSI) sequence for hyperpolarized 13C imaging on a clinical hybrid positron emission tomography/magnetic resonance imaging system. The pulse sequence uses parallel reconstruction pipelines to separately reconstruct data from odd-and-even gradient echoes to reduce artifacts from gradient imbalances. The ramp-sampled data in the spatiotemporal frequency space are regridded to compensate for the chemical-shift displacements. Unaliasing of nonoverlapping peaks outside of the sampled spectral width was performed to double the effective spectral width. The sequence was compared with conventional phase-encoded chemical-shift imaging (CSI) in phantoms, and it was evaluated in a canine cancer patient with ameloblastoma after injection of hyperpolarized [1-13C]pyruvate. The relative signal-to-noise ratio of EPSI with respect to CSI was 0.88, which is consistent with the decrease in sampling efficiency due to ramp sampling. Data regridding in the spatiotemporal frequency space significantly reduced spatial blurring compared with direct fast Fourier transform. EPSI captured the spatial distributions of both metabolites and their temporal dynamics in vivo with an in-plane spatial resolution of 5 × 9 mm2 and a temporal resolution of 3 seconds. Significantly higher spatial and temporal resolution for delineating anatomical structures in vivo was achieved for EPSI metabolic maps than for CSI maps, which suffered spatiotemporal blurring. The EPSI sequence showed promising results in terms of short acquisition time and sufficient spectral bandwidth of 500 Hz, allowing to adjust the trade-off between signal-to-noise ratio and encoding speed.
Original languageEnglish
JournalTomography - A Journal for Imaging Research
Volume4
Issue number3
Pages (from-to)110-122
ISSN2379-1381
DOIs
Publication statusPublished - 2018

Keywords

  • Hyperpolarization
  • Echo-planar spectroscopic imaging
  • Molecular imaging
  • Regridding
  • Metabolic imaging
  • Cancer

Cite this

Eldirdiri, Abubakr ; Posse, Stefan ; Hanson, Lars G. ; Hansen, Rie Beck ; Holst, Pernille ; Schøier, Christina ; Kristensen, Annemarie T ; Johannesen, Helle Hjorth ; Kjær, Andreas ; Hansen, Adam E ; Ardenkjær-Larsen, Jan Henrik. / Development of a Symmetric Echo-Planar Spectroscopy Imaging Framework for Hyperpolarized 13C Imaging in a Clinical PET/MR Scanner. In: Tomography - A Journal for Imaging Research. 2018 ; Vol. 4, No. 3. pp. 110-122.
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title = "Development of a Symmetric Echo-Planar Spectroscopy Imaging Framework for Hyperpolarized 13C Imaging in a Clinical PET/MR Scanner",
abstract = "Here, we developed a symmetric echo-planar spectroscopic imaging (EPSI) sequence for hyperpolarized 13C imaging on a clinical hybrid positron emission tomography/magnetic resonance imaging system. The pulse sequence uses parallel reconstruction pipelines to separately reconstruct data from odd-and-even gradient echoes to reduce artifacts from gradient imbalances. The ramp-sampled data in the spatiotemporal frequency space are regridded to compensate for the chemical-shift displacements. Unaliasing of nonoverlapping peaks outside of the sampled spectral width was performed to double the effective spectral width. The sequence was compared with conventional phase-encoded chemical-shift imaging (CSI) in phantoms, and it was evaluated in a canine cancer patient with ameloblastoma after injection of hyperpolarized [1-13C]pyruvate. The relative signal-to-noise ratio of EPSI with respect to CSI was 0.88, which is consistent with the decrease in sampling efficiency due to ramp sampling. Data regridding in the spatiotemporal frequency space significantly reduced spatial blurring compared with direct fast Fourier transform. EPSI captured the spatial distributions of both metabolites and their temporal dynamics in vivo with an in-plane spatial resolution of 5 × 9 mm2 and a temporal resolution of 3 seconds. Significantly higher spatial and temporal resolution for delineating anatomical structures in vivo was achieved for EPSI metabolic maps than for CSI maps, which suffered spatiotemporal blurring. The EPSI sequence showed promising results in terms of short acquisition time and sufficient spectral bandwidth of 500 Hz, allowing to adjust the trade-off between signal-to-noise ratio and encoding speed.",
keywords = "Hyperpolarization, Echo-planar spectroscopic imaging, Molecular imaging, Regridding, Metabolic imaging, Cancer",
author = "Abubakr Eldirdiri and Stefan Posse and Hanson, {Lars G.} and Hansen, {Rie Beck} and Pernille Holst and Christina Sch{\o}ier and Kristensen, {Annemarie T} and Johannesen, {Helle Hjorth} and Andreas Kj{\ae}r and Hansen, {Adam E} and Ardenkj{\ae}r-Larsen, {Jan Henrik}",
year = "2018",
doi = "10.18383/j.tom.2018.00006",
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Development of a Symmetric Echo-Planar Spectroscopy Imaging Framework for Hyperpolarized 13C Imaging in a Clinical PET/MR Scanner. / Eldirdiri, Abubakr; Posse, Stefan; Hanson, Lars G. ; Hansen, Rie Beck; Holst, Pernille; Schøier, Christina; Kristensen, Annemarie T; Johannesen, Helle Hjorth; Kjær, Andreas ; Hansen, Adam E; Ardenkjær-Larsen, Jan Henrik.

In: Tomography - A Journal for Imaging Research, Vol. 4, No. 3, 2018, p. 110-122.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Development of a Symmetric Echo-Planar Spectroscopy Imaging Framework for Hyperpolarized 13C Imaging in a Clinical PET/MR Scanner

AU - Eldirdiri, Abubakr

AU - Posse, Stefan

AU - Hanson, Lars G.

AU - Hansen, Rie Beck

AU - Holst, Pernille

AU - Schøier, Christina

AU - Kristensen, Annemarie T

AU - Johannesen, Helle Hjorth

AU - Kjær, Andreas

AU - Hansen, Adam E

AU - Ardenkjær-Larsen, Jan Henrik

PY - 2018

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N2 - Here, we developed a symmetric echo-planar spectroscopic imaging (EPSI) sequence for hyperpolarized 13C imaging on a clinical hybrid positron emission tomography/magnetic resonance imaging system. The pulse sequence uses parallel reconstruction pipelines to separately reconstruct data from odd-and-even gradient echoes to reduce artifacts from gradient imbalances. The ramp-sampled data in the spatiotemporal frequency space are regridded to compensate for the chemical-shift displacements. Unaliasing of nonoverlapping peaks outside of the sampled spectral width was performed to double the effective spectral width. The sequence was compared with conventional phase-encoded chemical-shift imaging (CSI) in phantoms, and it was evaluated in a canine cancer patient with ameloblastoma after injection of hyperpolarized [1-13C]pyruvate. The relative signal-to-noise ratio of EPSI with respect to CSI was 0.88, which is consistent with the decrease in sampling efficiency due to ramp sampling. Data regridding in the spatiotemporal frequency space significantly reduced spatial blurring compared with direct fast Fourier transform. EPSI captured the spatial distributions of both metabolites and their temporal dynamics in vivo with an in-plane spatial resolution of 5 × 9 mm2 and a temporal resolution of 3 seconds. Significantly higher spatial and temporal resolution for delineating anatomical structures in vivo was achieved for EPSI metabolic maps than for CSI maps, which suffered spatiotemporal blurring. The EPSI sequence showed promising results in terms of short acquisition time and sufficient spectral bandwidth of 500 Hz, allowing to adjust the trade-off between signal-to-noise ratio and encoding speed.

AB - Here, we developed a symmetric echo-planar spectroscopic imaging (EPSI) sequence for hyperpolarized 13C imaging on a clinical hybrid positron emission tomography/magnetic resonance imaging system. The pulse sequence uses parallel reconstruction pipelines to separately reconstruct data from odd-and-even gradient echoes to reduce artifacts from gradient imbalances. The ramp-sampled data in the spatiotemporal frequency space are regridded to compensate for the chemical-shift displacements. Unaliasing of nonoverlapping peaks outside of the sampled spectral width was performed to double the effective spectral width. The sequence was compared with conventional phase-encoded chemical-shift imaging (CSI) in phantoms, and it was evaluated in a canine cancer patient with ameloblastoma after injection of hyperpolarized [1-13C]pyruvate. The relative signal-to-noise ratio of EPSI with respect to CSI was 0.88, which is consistent with the decrease in sampling efficiency due to ramp sampling. Data regridding in the spatiotemporal frequency space significantly reduced spatial blurring compared with direct fast Fourier transform. EPSI captured the spatial distributions of both metabolites and their temporal dynamics in vivo with an in-plane spatial resolution of 5 × 9 mm2 and a temporal resolution of 3 seconds. Significantly higher spatial and temporal resolution for delineating anatomical structures in vivo was achieved for EPSI metabolic maps than for CSI maps, which suffered spatiotemporal blurring. The EPSI sequence showed promising results in terms of short acquisition time and sufficient spectral bandwidth of 500 Hz, allowing to adjust the trade-off between signal-to-noise ratio and encoding speed.

KW - Hyperpolarization

KW - Echo-planar spectroscopic imaging

KW - Molecular imaging

KW - Regridding

KW - Metabolic imaging

KW - Cancer

U2 - 10.18383/j.tom.2018.00006

DO - 10.18383/j.tom.2018.00006

M3 - Journal article

VL - 4

SP - 110

EP - 122

JO - Tomography - A Journal for Imaging Research

JF - Tomography - A Journal for Imaging Research

SN - 2379-1381

IS - 3

ER -