Human Brain Deuterium Metabolic Imaging at <scp>7 T</scp>: Impact of Different [6,6′‐<scp>²H₂</scp>]Glucose Doses

Abstract

Background Deuterium metabolic imaging (DMI) is an innovative, noninvasive metabolic MR imaging method conducted after administration of 2 H‐labeled substrates. DMI after [6,6′‐ 2 H 2 ]glucose consumption has been used to investigate brain metabolic processes, but the impact of different [6,6′‐ 2 H 2 ]glucose doses on DMI brain data is not well known. Purpose To investigate three different [6,6′‐ 2 H 2 ]glucose doses for DMI in the human brain at 7 T. Study Type Prospective. Population Six healthy participants (age: 28 ± 8 years, male/female: 3/3). Field Strength/Sequence 7 T, 3D 2 H free‐induction‐decay (FID)‐magnetic resonance spectroscopic imaging (MRSI) sequence. Assessment Three subjects received two different doses (0.25 g/kg, 0.50 g/kg or 0.75 g/kg body weight) of [6,6′‐ 2 H 2 ]glucose on two occasions and underwent consecutive 2 H‐MRSI scans for 120 minutes. Blood was sampled every 10 minutes during the scan, to determine plasma glucose levels and plasma 2 H‐Glucose atom percent excess (APE) (part‐1). Three subjects underwent the same protocol once after receiving 0.50 g/kg [6,6′‐ 2 H 2 ]glucose (part‐2). Statistical Test Mean plasma 2 H‐Glucose APE and glucose plasma concentrations were compared using one‐way ANOVA. Brain 2 H‐Glc and brain 2 H‐Glx (part‐1) were analyzed with a two‐level Linear Mixed Model. In part‐2, a General Linear Model was used to compare brain metabolite signals. Statistical significance was set at P &lt; 0.05. Results Between 60 and 100 minutes after ingesting [6,6′‐ 2 H 2 ]glucose, plasma 2 H‐Glc APE did not differ between 0.50 g/kg and 0.75 g/kg doses ( P = 0.961), but was significantly lower for 0.25 g/kg. Time and doses significantly affected brain 2 H‐Glucose levels (estimate ± standard error [SE]: 0.89 ± 0.01, 1.09 ± 0.01, and 1.27 ± 0.01, for 0.25 g/kg, 0.50 g/kg, and 0.75 g/kg, respectively) and brain 2 H‐Glutamate/Glutamine levels (estimate ± SE: 1.91 ± 0.03, 2.27 ± 0.03, and 2.46 ± 0.03, for 0.25 g/kg, 0.50 g/kg, and 0.75 g/kg, respectively). Plasma 2 H‐Glc APE, brain 2 H‐Glc, and brain 2 H‐Glx levels were comparable among subjects receiving 0.50 g/kg [6,6′‐ 2 H 2 ]glucose. Data Conclusion Brain 2 H‐Glucose and brain 2 H‐Glutamate/Glutamine showed to be [6,6′‐ 2 H 2 ]glucose dose dependent. A dose of 0.50 g/kg demonstrated comparable, and well‐detectable, 2 H‐Glucose and 2 H‐Glutamate/Glutamine signals in the brain. Evidence Level 1 Technical Efficacy Stage 2

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