To maximize sensitivity, the 2H signal is excited by a single RF pulse, after which spatial localization is achieved with short 3D phase encoding blips before FID acquisition. The low natural abundance of 2H of 0.0115% ( 6) leads to low-intensity water and lipid signals, thus eliminating the need for water and lipid suppression. DMI is characterized by its technical simplicity and robustness as well as the relatively high sensitivity due to the larger magnetic moment and short T 1 relaxation time constants. Common stable isotope methods include 13C MR spectroscopy (MRS) ( 2), inverse 1H- MRS ( 3) and hyperpolarized 13C MRS ( 4, 5).
DMI falls in the category of stable isotope methods in which an enriched substrate isotope is followed over time as it appears in down-stream metabolic products. With optimal multi-receiver arrays the acquisition of DMI at a nominal 1 mL spatial resolution is feasible at 7 T.ĭeuterium metabolic imaging (DMI) is a novel MR-based method to spatially map metabolism ( 1). The spectral resolution increases linearly due to near-constant linewidths. For larger human surface coils (Ø 80 mm) the sensitivity scales as a +1.65 power. These are in excellent agreement with theoretical predictions made from the principle of reciprocity for a coil-noise dominant regime. For small animal surface coils (Ø 30 mm), the experimentally measured sensitivity and transmit efficiency scale with the magnetic field to the power +1.75 and −0.30, respectively. The sensitivity and spectral resolution on human brain in vivo are investigated at 4 T and 7 T before and after an oral dose of -glucose. Here the magnetic field dependence of DMI sensitivity and transmit efficiency is studied on phantoms and rat brain post mortem at 4 T, 9.4 T and 11.7 T. Compared to traditional 13C-MR-based metabolic studies, the MR sensitivity of DMI is high due to the larger 2H magnetic moment and favorable T 1 and T 2 relaxation times. Deuterium metabolic imaging, or DMI, is a novel MR-based method to spatially map metabolism of deuterated substrates such as -glucose in vivo.
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