Phosphorus-31 magnetic resonance spectroscopic imaging (31P-MRSI) provides valuable non-invasive in vivo information on tissue metabolism but is burdened by poor sensitivity and prolonged scan duration. Ultra-short echo time (UTE) acquisitions minimize signal loss when probing signals with relatively short spin-spin relaxation time (T2), while also preventing first-order dephasing. Here, a three-dimensional (3D) UTE sequence with a rosette k-space trajectory is applied to 31P-MRSI at 3T. Conventional chemical shift imaging (CSI) employs highly regular Cartesian k-space sampling, susceptible to substantial artifacts when accelerated via undersampling. In contrast, this novel sequence’s “petal-like” pattern offers incoherent sampling more suitable for compressed sensing (CS). These results showcase the competitive performance of UTE rosette 31P-MRSI against conventional weighted CSI with simulation, phantom, and in vivo leg muscle comparisons.

1. 3D ultra-short echo time
31P-MRSI with rosette k-
space pattern: Feasibility
and comparison with
conventional weighted CSI
• Brian Bozymski1 Uzay Emir1 Ulrike Dydak1 Xin Shen2
M. Albert Thomas3 Ali Özen4 Mark Chiew5 William
Clarke5 Stephen Sawiak6
• 1 School of Health Sciences, Purdue University,
• 2 Radiology and Biomedical Imaging, University of
California San Francisco,
• 3 Department of Radiology, University of California,
• 4 Department of Radiology, Medical Physics, Medical
Center - University of Freiburg,
• 5 Wellcome Centre for Integrative Neuroimaging,
FMRIB, Nuffield Department of Clinical Neurosciences,
• 6 Department of Clinical Neuroscience, University of
Cambridge