On the magnetic field dependence of deuterium metabolic imaging

Deuterium metabolic imaging (DMI) is a novel MR‐based method to spatially map metabolism of deuterated substrates such as [6,6'‐2H2]‐glucose in vivo. Compared with traditional 13C‐MR‐based metabolic studies, the MR sensitivity of DMI is high due to the larger 2H magnetic moment and favorable T1 and T2 relaxation times. Here, the magnetic field dependence of DMI sensitivity and transmit efficiency is studied on phantoms and rat brain postmortem at 4, 9.4 and 11.7 T. The sensitivity and spectral resolution on human brain in vivo are investigated at 4 and 7 T before and after an oral dose of [6,6'‐2H2]‐glucose. For small animal surface coils (Ø 30 mm), the experimentally measured sensitivity and transmit efficiency scale with the magnetic field to a power of +1.75 and −0.30, respectively. These are in excellent agreement with theoretical predictions made from the principle of reciprocity for a coil noise‐dominant regime. For larger human surface coils (Ø 80 mm), the sensitivity scales as a +1.65 power. The spectral resolution increases linearly due to near‐constant linewidths. With optimal multireceiver arrays the acquisition of DMI at a nominal 1 mL spatial resolution is feasible at 7 T. The magnetic field dependence of deuterium metabolic imaging (DMI) sensitivity and RF efficiency was investigated on phantoms in vitro, rat brain postmortem and human brain in vivo. The sensitivity scaled supralinearly, close to the theoretical maximum for all conditions. The enhanced sensitivity at 7 T makes DMI at a nominal 1 mL spatial resolution feasible.