%0 Journal Article
%A Blömer, Simon
%A Hingerl, Lukas
%A Marjańska, Małgorzata
%A Bogner, Wolfgang
%A Motyka, Stanislav
%A Hangel, Gilbert
%A Klauser, Antoine
%A Andronesi, Ovidiu C
%A Strasser, Bernhard
%T Proton-free induction decay MRSI at 7 T in the human brain using an egg-shaped modified rosette K-space trajectory.
%J Magnetic resonance in medicine
%V 93
%N 4
%@ 1522-2594
%C New York, NY [u.a.]
%I Wiley-Liss
%M DZNE-2025-00292
%P 1443 - 1457
%D 2025
%X 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
%K Humans
%K Phantoms, Imaging
%K Brain: diagnostic imaging
%K Algorithms
%K Signal-To-Noise Ratio
%K Adult
%K Magnetic Resonance Imaging: methods
%K Protons
%K Computer Simulation
%K Male
%K Reproducibility of Results
%K Female
%K Image Processing, Computer-Assisted: methods
%K Healthy Volunteers
%K 7 T (Other)
%K SNR efficiency (Other)
%K gradient hardware restrictions (Other)
%K magnetic resonance spectroscopic imaging (Other)
%K modified rosette trajectory (Other)
%K non‐Cartesian trajectory (Other)
%K Protons (NLM Chemicals)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:39568225
%2 pmc:PMC11782714
%R 10.1002/mrm.30368
%U https://pub.dzne.de/record/276344