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Application of flow sensitive gradients for improved measures of metabolism using hyperpolarized 13 c MRI
Author(s) -
Gordon Jeremy W.,
Niles David J.,
Adamson Erin B.,
Johnson Kevin M.,
Fain Sean B.
Publication year - 2016
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.25584
Subject(s) - nuclear magnetic resonance , hyperpolarization (physics) , nuclear magnetic resonance spectroscopy , chemistry , physics
Purpose To develop the use of bipolar gradients to suppress partial‐volume and flow‐related artifacts from macrovascular, hyperpolarized spins. Theory and Methods Digital simulations were performed over a range of spatial resolutions and gradient strengths to determine the optimal bipolar gradient strength and duration to suppress flowing spins while minimizing signal loss from static tissue. In vivo experiments were performed to determine the efficacy of this technique to suppress vascular signal in the study of hyperpolarized [1‐ 13 C]pyruvate renal metabolism. Results Digital simulations showed that in the absence of bipolar gradients, partial‐volume artifacts from the vasculature were still present, causing underestimation of the apparent reaction rate of pyruvate to lactate ( k P ). The addition of a bipolar gradient with b = 32 s/mm 2 sufficiently suppressed the vascular signal without a substantial decrease in signal from static tissue. In vivo results corroborate digital simulations, with similar peak lactate signal to noise ratio (SNR) but substantially different k P in the presence of bipolar gradients. Conclusion The proposed approach suppresses signal from flowing spins while minimizing signal loss from static tissue, removing contaminating signal from the vasculature and increasing kinetic modeling accuracy without substantially sacrificing SNR or temporal resolution. Magn Reson Med 75:1242–1248, 2016. © 2015 Wiley Periodicals, Inc.