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Abstract #4296

Ratiometric Analysis of Hyperpolarized 13C-NMR Data to Quantify Reaction Rate Constants

Lin Z. Li1, 2, Stephen Kadlececk1, Ben Pullinger1, He N. Xu1, Dania Daye3, 4, Lewis Chodosh3, Rahim Rizi1

1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Britton Chance Lab of Redox Imaging, Johnson Research Foundation, University of Pennsylvania, Philadelphia, PA, United States; 3Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA, United States; 4Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States

Various modeling methods have been used to analyze in vivo hyperpolarized 13C-NMR data from the lactate dehydrogenase (LDH) reaction, which converts pyruvate to lactate. However, these models make certain assumptions about transport in the blood, across cell membranes, and/or enzymatic kinetics, and require at least 3 modeling parameters. Here we present a new method which relaxes some of these assumptions and minimizes the modeling parameters. By fitting the lactate/pyruvate ratio in mouse tumor models we quantify both the forward and reverse exchange rate constants of the LDH reaction. First order temporal derivatives of the lactate/pyruvate ratio help to determine the proper time range for fitting.

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Keywords

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