Journal Article

DZNE-2025-00292

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Proton-free induction decay MRSI at 7 T in the human brain using an egg-shaped modified rosette K-space trajectory.

Blömer, S. (First author)DZNE* ; Hingerl, L. ; Marjańska, M. ; Bogner, W. ; Motyka, S. ; Hangel, G. ; Klauser, A. ; Andronesi, O. C. ; Strasser, B.

2025
Wiley-Liss New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1002/mrm.30368

Abstract: Proton (1H)-MRSI via spatial-spectral encoding poses high demands on gradient hardware at ultra-high fields and high-resolutions. Rosette trajectories help alleviate these problems, but at reduced SNR-efficiency because of their k-space densities not matching any desired k-space filter. We propose modified rosette trajectories, which more closely match a Hamming filter, and thereby improve SNR performance while still staying within gradient hardware limitations and without prolonging scan time.Analytical and synthetic simulations were validated with phantom and in vivo measurements at 7 T. The rosette and modified rosette trajectories were measured in five healthy volunteers in 6 min in a 2D slice in the brain. An elliptical phase-encoding sequence was measured in one volunteer in 22 min, and a 3D sequence was measured in one volunteer within 19 min. The SNR per-unit-time, linewidth, Cramer-Rao lower bounds (CRLBs), lipid contamination, and data quality of the proposed modified rosette trajectory were compared to the rosette trajectory.Using the modified rosette trajectories, an improved k-space weighting function was achieved resulting in an SNR per-unit-time increase of up to 12% compared to rosette's and 23% compared to elliptical phase-encoding, dependent on the two additional trajectory parameters. Similar results were achieved for the theoretical SNR calculation based on k-space densities, as well as when using the pseudo-replica method for simulated, in vivo, and phantom data. The CRLBs of γ-aminobutyric acid and N-acetylaspartylglutamate improved non-significantly for the modified rosette trajectory, whereas the linewidths and lipid contamination remained similar.By optimizing the shape of the rosette trajectory, the modified rosette trajectories achieved higher SNR per-unit-time and enhanced data quality at the same scan time.

Keyword(s): Humans (MeSH) ; Phantoms, Imaging (MeSH) ; Brain: diagnostic imaging (MeSH) ; Algorithms (MeSH) ; Signal-To-Noise Ratio (MeSH) ; Adult (MeSH) ; Magnetic Resonance Imaging: methods (MeSH) ; Protons (MeSH) ; Computer Simulation (MeSH) ; Male (MeSH) ; Reproducibility of Results (MeSH) ; Female (MeSH) ; Image Processing, Computer-Assisted: methods (MeSH) ; Healthy Volunteers (MeSH) ; 7 T ; SNR efficiency ; gradient hardware restrictions ; magnetic resonance spectroscopic imaging ; modified rosette trajectory ; non‐Cartesian trajectory ; Protons

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Contributing Institute(s):

1. Patient Studies (Bonn) (Patient Studies (Bonn))

Research Program(s):

1. 353 - Clinical and Health Care Research (POF4-353) (POF4-353)

Appears in the scientific report 2025

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Database coverage:
; ; ; BIOSIS Previews ; Biological Abstracts ; Clarivate Analytics Master Journal List ; Current Contents - Clinical Medicine ; Current Contents - Life Sciences ; DEAL Wiley ; Essential Science Indicators ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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