Title: Improved reconstruction stability for chemical shift encoded hyperpolarized ¹³ C magnetic resonance spectroscopic imaging using k‐t spiral acquisitions

Abstract

Purpose A multiecho, field of view (FOV)‐oversampled k‐t spiral acquisition and direct iterative decomposition of water and fat with echo asymmetry and least‐squares estimation reconstruction is demonstrated to improve the stability of hyperpolarized ¹³ C magnetic resonance spectroscopic imaging (MRSI) in the presence of signal ambiguities attributed to low‐SNR (signal‐to‐noise‐ratio) species, local uncertainties in metabolite peaks, and echo‐to‐echo signal inconsistencies. Theory k‐t spiral acquisitions redistribute readout points to be more densely spaced radially in k‐space by acquiring an FOV and matrix that are oversampled by η . These more densely spaced spiral turns constitute effective intraspiral echoes and can supplement conventional interspiral echoes to improve spectral separation and reduce spectral cross‐talk to better resolve ¹³ C‐labeled species for spectroscopic imaging. Methods Digital simulations and imaging phantom experiments were performed for a range of interspiral echo spacings and η using multiecho, k‐t spiral acquisitions. Image spectral cross‐talk artifacts were evaluated both qualitatively and quantitatively as the percent error in measured metabolite ratios. In vivo murine experiments evaluated the feasibility of multiecho, k‐t spiral [1‐ ¹³ C]pyruvate MRSI to reduce spectral cross‐talk for 3 scenarios of different expected reconstruction stability. Results Digital simulations and imaging phantom experiments both demonstrated reduced or comparablemore » image spectral cross‐talk and percent errors in measured metabolite ratios with increasing η and better choices of echo spacings. In vivo images displayed markedly reduced spectral cross‐talk in lactate images acquired with η = 7 versus η = 1. Conclusion The precision of hyperpolarized ¹³ C metabolic imaging and quantification in the presence of low‐SNR species, local uncertainties in metabolite resonances, and echo‐to‐echo signal inconsistencies can be improved with the use of FOV‐oversampled k‐t spiral acquisitions.« less

Authors:

Macdonald, Erin B.  ^[1];

• Search DOE PAGES for author "Macdonald, Erin B."
• Search DOE PAGES for ORCID "0000-0002-3065-8538"

Barton, Gregory P.  ^[1];

• Search DOE PAGES for author "Barton, Gregory P."
• Search DOE PAGES for ORCID "0000-0001-7471-5488"

Cox, Benjamin L. ^[2]; Johnson, Kevin M. ^[3]; Strigel, Roberta M. ^[4]; Fain, Sean B.  ^[5]

• Search DOE PAGES for author "Fain, Sean B."
• Search DOE PAGES for ORCID "0000-0001-5461-0646"

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+ Show Author Affiliations

1. Department of Medical Physics University of Wisconsin‐Madison Madison Wisconsin
2. Department of Medical Physics University of Wisconsin‐Madison Madison Wisconsin, Morgridge Institute for Research University of Wisconsin‐Madison Madison Wisconsin, Laboratory for Optical and Computational Instrumentation University of Wisconsin‐Madison Madison Wisconsin
3. Department of Medical Physics University of Wisconsin‐Madison Madison Wisconsin, Department of Radiology University of Wisconsin‐Madison Madison Wisconsin
4. Department of Medical Physics University of Wisconsin‐Madison Madison Wisconsin, Department of Radiology University of Wisconsin‐Madison Madison Wisconsin, Carbone Cancer Center University of Wisconsin‐Madison Madison Wisconsin
5. Department of Medical Physics University of Wisconsin‐Madison Madison Wisconsin, Department of Radiology University of Wisconsin‐Madison Madison Wisconsin, Department of Biomedical Engineering University of Wisconsin‐Madison Madison Wisconsin

Publication Date:

Mon Dec 09 00:00:00 EST 2019

Sponsoring Org.:

USDOE

OSTI Identifier:

1577881

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Magnetic Resonance in Medicine

Additional Journal Information:

Journal Name: Magnetic Resonance in Medicine Journal Volume: 84 Journal Issue: 1; Journal ID: ISSN 0740-3194

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United States

Language:

English