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

Abstract

BackgroundDeuterium metabolic imaging (DMI) is an innovative, noninvasive metabolic MR imaging method conducted after administration of 2H‐labeled substrates. DMI after [6,6′‐2H2]glucose consumption has been used to investigate brain metabolic processes, but the impact of different [6,6′‐2H2]glucose doses on DMI brain data is not well known.PurposeTo investigate three different [6,6′‐2H2]glucose doses for DMI in the human brain at 7 T.Study TypeProspective.PopulationSix healthy participants (age: 28 ± 8 years, male/female: 3/3).Field Strength/Sequence7 T, 3D 2H free‐induction‐decay (FID)‐magnetic resonance spectroscopic imaging (MRSI) sequence.AssessmentThree subjects received two different doses (0.25 g/kg, 0.50 g/kg or 0.75 g/kg body weight) of [6,6′‐2H2]glucose on two occasions and underwent consecutive 2H‐MRSI scans for 120 minutes. Blood was sampled every 10 minutes during the scan, to determine plasma glucose levels and plasma 2H‐Glucose atom percent excess (APE) (part‐1). Three subjects underwent the same protocol once after receiving 0.50 g/kg [6,6′‐2H2]glucose (part‐2).Statistical TestMean plasma 2H‐Glucose APE and glucose plasma concentrations were compared using one‐way ANOVA. Brain 2H‐Glc and brain 2H‐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 < 0.05.ResultsBetween 60 and 100 minutes after ingesting [6,6′‐2H2]glucose, plasma 2H‐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 2H‐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 2H‐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 2H‐Glc APE, brain 2H‐Glc, and brain 2H‐Glx levels were comparable among subjects receiving 0.50 g/kg [6,6′‐2H2]glucose.Data ConclusionBrain 2H‐Glucose and brain 2H‐Glutamate/Glutamine showed to be [6,6′‐2H2]glucose dose dependent. A dose of 0.50 g/kg demonstrated comparable, and well‐detectable, 2H‐Glucose and 2H‐Glutamate/Glutamine signals in the brain.Evidence Level1Technical EfficacyStage 2