Advanced methods for in vivo magnetic resonance spectroscopy of 1H and hyperpolarized 13C

Magnetic resonance spectroscopy enables the in-vivo and non-invasive measurement of concentrations of metabolites containing protons (1H) or carbon isotopes (13C). In the present work, robust radiofrequency pulses were optimized for this application and for the generation of spin-echo signals. These pulses were validated by localized 1H spectroscopy in phantoms and human brains. Furthermore, spectra originating from intravenous injections of hyperpolarized 13C pyruvate, showing also downstream metabolites lactate, alanine, and bicarbonate, were quantified by adapting available spectral quantification programs and developing a fully-automatic algorithm. In addition, the effects of the relatively large injected 13C pyruvate dose on saturation of the metabolism were examined and guidelines on the optimal dose are given.