Deuterium metabolic imaging in the human brain at 9.4 Tesla with high spatial and temporal resolution

Abstract

Purpose To present first highly spatially resolved deuterium metabolic imaging (DMI) measurements of the human brain acquired with a dedicated coil design and a fast chemical shift imaging (CSI) sequence at an ultrahigh field strength of B 0 = 9.4 T. 2 H metabolic measurements with a temporal resolution of 10 min enabled the investigation of the glucose metabolism in healthy human subjects. Methods The study was performed with a double-tuned coil with 10 TxRx channels for 1 H and 8TxRx/2Rx channels for 2 H and an Ernst angle 3D CSI sequence with a nominal spatial resolution of 2.97 ml and a temporal resolution of 10 min. Results The metabolism of [6,6′- 2 H 2 ]-labeled glucose due to the TCA cycle could be made visible in high resolution metabolite images of deuterated water, glucose and Glx over the entire human brain. Conclusion X-nuclei MRSI as DMI can highly benefit from ultrahigh field strength enabling higher temporal and spatial resolutions.

Deuterium metabolic imaging and hyperpolarized13C-MRI of the normal human brain at clinical field strength reveals differential cerebral metabolism

“…This work could not separate 2 H-lactate from 2 H-lipids, although the 1.35 ppm peak increased by 93% in the first experiment, suggesting that about half the measured peak is likely from the formation of lactate. This contrasts with a recent study in humans at 9.4 T (Ruhm et al, 2021), which found the lipid signal exceeded lactate, which may be the result of using a surface array coil for reception. In comparison with the birdcage coil used here, surface arrays greatly amplify signal from scalp lipids.…”

“…One of the major challenges in undertaking a direct comparison between the two techniques in humans is that 13 C-HPMRI is usually undertaken at 3 T, which allows good spectral separation of metabolites while maintaining a sufficiently long relaxation time for the hyperpolarized signal to enable detection of both the injected hyperpolarized substrate and the subsequently formed metabolites (Vaeggemose et al, 2021). In comparison, DMI has been applied at field strengths of up to 16.4 T for improved spectral separation and signal-to-noise (Lu et al, 2017), with clinical DMI having previously been undertaken at field strengths of 4 T and higher, which are not used in routine clinical practice (De Feyter et al, 2018; de Graaf et al, 2020; Ruhm et al, 2021).…”

“…13 C-HPMRI demonstrated differences between gray and white matter which were not seen with DMI and may have been identified if a higher spatial resolution was used. One study at a higher field strength of 9.4 T demonstrated higher Glx continuing to increase in gray matter compared to white matter up to two hours after oral administration of 2 H-glucose (Ruhm et al, 2021). The intravenous administration of 2 H-glucose would result in higher in vivo concentrations thus increasing SNR, enabling higher resolution DMI at 3 T.…”

“…DMI is most frequently undertaken with oral deuterated [6,6’- 2 H 2 ]glucose to detect the subsequent formation of its downstream metabolites: 2 H-lactate (predominately [3,3’- 2 H 2 ]lactate but also [3-H 2 ]lactate), 2 H-Glx (a combined peak of [4,4’- 2 H 2 ]glutamate, [4- 2 H]glutamate, [4’- 2 H]glutamate, [4,4’- 2 H 2 ]glutamine, [4- 2 H]glutamine, and [4’- 2 H]glutamine), and deuterated water ( 2 H-water or HDO). In vivo DMI studies published to date have utilized high field strength systems greater than 3 T (De Feyter et al, 2018; de Graaf et al, 2020; Ruhm et al, 2021), but for the technique to be used more widely, translation to clinical field strengths and clinical MR systems is required. Here we demonstrate the potential of DMI at 3 T for the first time.…”

Interleaved fluid‐attenuated inversion recovery (FLAIR) MRI and deuterium metabolic imaging (DMI) on human brain in vivo

“…Since its development, DMI has been used to evaluate glucose metabolism in healthy animal 9 and human 8 brain, to characterize glioblastoma brain tumors (GBM) in humans 8 and animals 10 via the Warburg effect, and to assess brown adipose tissue 11 as well as myocardial tissue 12 . Most recently, the performance of DMI has been demonstrated at 9.4T, 13 substantiating the previous sensitivity prediction 14 . In addition to its promising performance and extensive applications, DMI is robust and simple to perform, suggesting a high potential to be transformed into a clinical metabolic imaging method.…”