Hyla Allouche-Arnon1, Lanette J. Friesen-Walder2, 3, Ayelet Gamliel1, Jacob Sosna1, J Moshe Gomori1, Rachel Katz-Brull1, 4
1Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel; 2Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 3Robarts Research Institute, London, Ontario, Canada; 4BrainWatch Ltd., Tel-Aviv, Israel
The purpose of this study was to determine if the prolonged T1 of 13C nuclei in choline due to deuteration would allow monitoring of choline oxidase activity using hyperpolarised 13C MRI/S. In vitro thermal equilibrium spectra showed oxidation of choline by choline oxidase from Alcaligenes to betaine aldehyde hydrate and betaine. Deuteration of the choline resulted in decreased enzymatic reaction yield, but the prolonged T1 was required for hyperpolarised 13C studies. Hyperpolarised [1,1,2,2-D4,2-13C]choline was mixed with choline oxidase and dynamic spectra were acquired at 3T. Build-up of the metabolic products, [1,2,2-D3,2-13C]betaine aldehyde hydrate and [2,2-D2,2-13C]betaine was clearly detected.