How deuterated tracers allow us imaging metabolism in vivo

Magnetic resonance has revolutionized medical diagnostics and chemical analysis alike. The miniscule magnetic moment of nuclear spins has proven exceptionally useful for resolving molecular structures, identifying chemicals and imaging anatomy and functions in vivo. 

Still, there is a large, unmet need in medicine for measuring (ideally imaging!) the biochemistry or metabolism underlying anatomy. 

Here, in vivo magnetic resonance spectroscopy offers unique insights. It is, however, severely hampered by the signal to noise which can be acquired in reasonable time. As a result, most of the time, only the large metabolite pools at mM concentrations can be detected in vivo. 

Two old but new approaches are currently in the spotlight for addressing this matter: hyperpolarized MR, where the alignment of the nuclear spins of a tracer is increased, and deuterium MR, where deuterated molecules are used to trace metabolism. The latter, the focus of this presentation, takes advantage of the fact that deuterium recovers much faster from excitation than hydrogen, so that many more averages can be acquired to increase the signal. In addition, the background signal is quite low, given a natural abundance of 0.015 %, so that the desired signal is not overlayed by unwanted signals as it is the case in hydrogen MR. Last but not least, it is relatively easy to deuterate molecules, such as glucose. I will expand on this matter in this presentation and reflect on recent developments in the field.