Deuterium metabolic imaging of the human brain in vivo at 7 T

Purpose To explore the potential of deuterium metabolic imaging (DMI) in the human brain in vivo at 7 T, using a multi-element deuterium (H-2) RF coil for 3D volume coverage. Methods H-1-MR images and localized H-2 MR spectra were acquired in vivo in the human brain of 3 healthy subjects to generate DMI maps of H-2-labeled water, glucose, and glutamate/glutamine (Glx). In addition, non-localized H-2-MR spectra were acquired both in vivo and in vitro to determine T-1 and T-2 relaxation times of deuterated metabolites at 7 T. The performance of the H-2 coil was assessed through numeric simulations and experimentally acquired B-1(+) maps. Results 3D DMI maps covering the entire human brain in vivo were obtained from well-resolved deuterated (H-2) metabolite resonances of water, glucose, and Glx. The T-1 and T-2 relaxation times were consistent with those reported at adjacent field strengths. Experimental B-1(+) maps were in good agreement with simulations, indicating efficient and homogeneous B-1(+) transmission and low RF power deposition for H-2, consistent with a similar array coil design reported at 9.4 T. Conclusion Here, we have demonstrated the successful implementation of 3D DMI in the human brain in vivo at 7 T. The spatial and temporal nominal resolutions achieved at 7 T (i.e., 2.7 mL in 28 min, respectively) were close to those achieved at 9.4 T and greatly outperformed DMI at lower magnetic fields. DMI at 7 T and beyond has clear potential in applications dealing with small brain lesions.

Automated summary

In this study, we successfully implemented 3D deuterium metabolic imaging (DMI) in the human brain in vivo at 7 T. The DMI maps of deuterium-labeled water, glucose, and glutamate/glutamine (Glx) were obtained with high resolution. The spatial and temporal resolutions achieved at 7 T were close to those at 9.4 T and outperformed DMI at lower magnetic fields, demonstrating the clear potential of DMI at 7 T and beyond in applications dealing with small brain lesions.