TY  - JOUR
AU  - Blömer, Simon
AU  - Hingerl, Lukas
AU  - Marjańska, Małgorzata
AU  - Bogner, Wolfgang
AU  - Motyka, Stanislav
AU  - Hangel, Gilbert
AU  - Klauser, Antoine
AU  - Andronesi, Ovidiu C
AU  - Strasser, Bernhard
TI  - Proton-free induction decay MRSI at 7 T in the human brain using an egg-shaped modified rosette K-space trajectory.
JO  - Magnetic resonance in medicine
VL  - 93
IS  - 4
SN  - 1522-2594
CY  - New York, NY [u.a.]
PB  - Wiley-Liss
M1  - DZNE-2025-00292
SP  - 1443 - 1457
PY  - 2025
AB  - 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
KW  - Humans
KW  - Phantoms, Imaging
KW  - Brain: diagnostic imaging
KW  - Algorithms
KW  - Signal-To-Noise Ratio
KW  - Adult
KW  - Magnetic Resonance Imaging: methods
KW  - Protons
KW  - Computer Simulation
KW  - Male
KW  - Reproducibility of Results
KW  - Female
KW  - Image Processing, Computer-Assisted: methods
KW  - Healthy Volunteers
KW  - 7 T (Other)
KW  - SNR efficiency (Other)
KW  - gradient hardware restrictions (Other)
KW  - magnetic resonance spectroscopic imaging (Other)
KW  - modified rosette trajectory (Other)
KW  - non‐Cartesian trajectory (Other)
KW  - Protons (NLM Chemicals)
LB  - PUB:(DE-HGF)16
C6  - pmid:39568225
C2  - pmc:PMC11782714
DO  - DOI:10.1002/mrm.30368
UR  - https://pub.dzne.de/record/276344
ER  -