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Quantified p H imaging with hyperpolarized 13 C ‐bicarbonate
Author(s) -
Scholz David Johannes,
Janich Martin A.,
Köllisch Ulrich,
Schulte Rolf F.,
ArdenkjaerLarsen Jan H.,
Frank Annette,
Haase Axel,
Schwaiger Markus,
Menzel Marion I.
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.25357
Subject(s) - in vivo , bicarbonate , chemistry , alkalosis , in vitro , nuclear magnetic resonance , biophysics , biochemistry , acidosis , medicine , biology , microbiology and biotechnology , organic chemistry , physics
Purpose Because pH plays a crucial role in several diseases, it is desirable to measure pH in vivo noninvasively and in a spatially localized manner. Spatial maps of pH were quantified in vitro, with a focus on method‐based errors, and applied in vivo. Methods In vitro and in vivo 13 C mapping were performed for various flip angles for bicarbonate (BiC) and CO 2 with spectral‐spatial excitation and spiral readout in healthy Lewis rats in five slices. Acute subcutaneous sterile inflammation was induced with Concanavalin A in the right leg of Buffalo rats. pH and proton images were measured 2 h after induction. Results After optimizing the signal to noise ratio of the hyperpolarized 13 C‐bicarbonate, error estimation of the spectral‐spatial excited spectrum reveals that the method covers the biologically relevant pH range of 6 to 8 with low pH error (< 0.2). Quantification of pH maps shows negligible impact of the residual bicarbonate signal. pH maps reflect the induction of acute metabolic alkalosis. Inflamed, infected regions exhibit lower pH. Conclusion Hyperpolarized 13 C‐bicarbonate pH mapping was shown to be sensitive in the biologically relevant pH range. The mapping of pH was applied to healthy in vivo organs and interpreted within inflammation and acute metabolic alkalosis models. Magn Reson Med 73:2274–2282, 2015. © 2014 Wiley Periodicals, Inc.