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A 2DRF pulse sequence for bolus tracking in hyperpolarized 13 C imaging
Author(s) -
Tang Shuyu,
Jiang Wenwen,
Chen HsinYu,
Bok Robert,
Vigneron Daniel B.,
Larson Peder E. Z.
Publication year - 2015
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.25427
Subject(s) - hyperpolarization (physics) , pulse sequence , excitation , nuclear magnetic resonance , bolus (digestion) , in vivo , scanner , chemistry , materials science , optics , biomedical engineering , physics , medicine , nuclear magnetic resonance spectroscopy , biology , surgery , microbiology and biotechnology , quantum mechanics
Purpose A novel application of two‐dimensional (2D) spatially selective radiofrequency (2DRF) excitation pulses in hyperpolarized13 C imaging is proposed for monitoring the bolus injection with highly efficient sampling of the initially polarized substrate, thus leaving more polarization available for detection of the subsequently generated metabolic products. Methods A 2DRF pulse was designed with a spiral trajectory and conventional clinical gradient performance. To demonstrate the ability of our 2DRF bolus tracking pulse sequence, hyperpolarized [1‐13 C ]pyruvate in vivo imaging experiments were performed in normal rats, with a comparison to 1DRF excitation pulses. Results Our designed 2DRF pulse was able to rapidly and efficiently monitor the injected bolus dynamics in vivo, with an 8‐fold enhanced time resolution in comparison with 1DRF in our experimental settings. When applied at the pyruvate frequency for bolus tracking, our 2DRF pulse demonstrated reduced saturation of the hyperpolarization for the substrate and metabolic products compared to a 1DRF pulse, while being immune to ±0.5 ppm magnetic field inhomogeneity at 3T. Conclusion 2DRF pulses in hyperpolarized13 C imaging can be used to efficiently monitor the bolus injection with reduced hyperpolarization saturation compared to 1DRF pulses. The parameters of our design are based on clinical scanner limits, which allows for rapid translation to human studies. Magn Reson Med 74:506–512, 2015. © 2014 Wiley Periodicals, Inc.