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Prospective acceleration of whole‐brain CEST imaging by golden‐angle view ordering in Cartesian coordinates and joint k‐space and image‐space parallel imaging (KIPI)

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Magnetic Resonance in Medicine
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Purpose To prospectively accelerate whole‐brain CEST acquisition by joint k‐space and image‐space parallel imaging (KIPI) with a proposed golden‐angle view ordering technique (GAVOT) in Cartesian coordinates. Theory and Methods The T2‐decay effect will vary across frames with variable acceleration factors (AF) in the prospective acquisition using sequences with long echo trains. The GAVOT method uses a subset strategy to eliminate the T2‐decay inconsistency, where all frames use a subset of shots from the calibration frame to form their k‐space view ordering. The golden‐angle rule is adapted to ensure uniform k‐space coverage for arbitrary AFs in Cartesian coordinates. Phantom and in vivo studies were conducted on a 3 T scanner. Results The GAVOT view ordering yielded a higher g‐factor than conventional uniformly centric ordering, whereas the noise propagation in amide proton transfer (APT) weighted images was similar between different view ordering. Compared to centric ordering, GAVOT successfully eliminated the T2‐decay inconsistency across all frames, resulting in fewer image artifacts for both KIPI and conventional parallel imaging methods. The synergy of GAVOT and KIPI mitigated strong aliasing artifacts and achieved high‐quality reconstruction of prospective variable‐AF datasets. GAVOT‐KIPI reduced the scan time to 2.1 min for whole‐brain APT weighted imaging and 4.7 min for quantitative APT signal (APT#) mapping. Conclusion GAVOT makes the prospective variable AF strategy flexible and practical, and, in conjunction with KIPI, ensures high‐quality reconstruction from highly undersampled data, facilitating the clinical translation of whole‐brain CEST imaging.
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Received: 25 August 2024 Revised: 16 October 2024 Accepted: 29 October 2024
DOI: 10.1002/mrm.30375
RESEARCH ARTICLE
Prospective acceleration of whole-brain CEST imaging by
golden-angle view ordering in Cartesian coordinates and
joint k-space and image-space parallel imaging (KIPI)
Tao Zu1Xingwang Yong1Zhechuan Dai1Tongling Jiang1Yi-Cheng Hsu2
Shanshan Lu3Yi Zhang1
1Key Laboratory for Biomedical
Engineering of Ministry of Education,
Department of Biomedical Engineering,
College of Biomedical Engineering and
Instrument Science, Zhejiang University,
Hangzhou, China
2MR Collaboration, Siemens Healthcare,
Shanghai, China
3The First Affiliated Hospital of Nanjing
Medical University, Nanjing, China
Correspondence
Yi Zhang, Room 322, Zhou Yiqing
Building, Yuquan Campus, Zhejiang
University, 38 Zheda Road, Hangzhou
310027, China.
Email: yizhangzju@zju.edu.cn
Funding information
National Key Research and Development
Program of China, Grant/Award Number:
2023YFE0210300; Key Research and
Development Program of Zhejiang
Province, Grant/Award Number:
2022C04031; Fundamental Research
Funds for the Central Universities,
Grant/Award Numbers: 2023ZFJH01-01,
2024ZFJH01-01; Leading Innovation and
Entrepreneurship Team of Zhejiang
Province, Grant/Award Number:
2020R01003
Abstract
Purpose: To prospectively accelerate whole-brain CEST acquisition by joint
k-space and image-space parallel imaging (KIPI) with a proposed golden-angle
view ordering technique (GAVOT) in Cartesian coordinates.
TheoryandMethods:The T2-decay effect will vary across frames with variable
acceleration factors (AF) in the prospective acquisition using sequences with
long echo trains. The GAVOT method uses a subset strategy to eliminate the
T2-decay inconsistency, where all frames use a subset of shots from the calibra-
tion frame to form their k-space view ordering. The golden-angle rule is adapted
to ensure uniform k-space coverage for arbitrary AFs in Cartesian coordinates.
Phantom and in vivo studies were conducted on a 3T scanner.
Results: The GAVOT view ordering yielded a higher g-factor than conventional
uniformly centric ordering, whereas the noise propagation in amide proton
transfer (APT) weighted images was similar between different view ordering.
Compared to centric ordering, GAVOT successfully eliminated the T2-decay
inconsistency across all frames, resulting in fewer image artifacts for both KIPI
and conventional parallel imaging methods. The synergy of GAVOT and KIPI
mitigated strong aliasing artifacts and achieved high-quality reconstruction of
prospective variable-AF datasets. GAVOT-KIPI reduced the scan time to 2.1min
for whole-brain APT weighted imaging and 4.7min for quantitative APT signal
(APT#) mapping.
Conclusion: GAVOT makes the prospective variable AF strategy flexible and
practical, and, in conjunction with KIPI, ensures high-quality reconstruc-
tion from highly undersampled data, facilitating the clinical translation of
whole-brain CEST imaging.
KEYWORDS
chemical exchange saturation transfer (CEST), fast imaging, golden-angle view ordering
technique (GAVOT), joint k-space and image-space parallel imaging (KIPI)
© 2024 International Society for Magnetic Resonance in Medicine.
Magn Reson Med. 2025;93:1585–1601. wileyonlinelibrary.com/journal/mrm 1585
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