3D 31P MRSI of the human brain at 9.4 Tesla: Optimization and quantitative analysis of metabolic images

Abstract

Purpose: To present 31P whole brain MRSI with a high spatial resolution to probe quantitative tissue analysis of 31P MRSI at an ultrahigh field strength of 9.4 Tesla. Methods: The study protocol included a 31P MRSI measurement with an effective resolution of 2.47 mL. For SNR optimization, the nuclear Overhauser enhancement at 9.4 Tesla was investigated. A sensitivity correction was achieved by applying a low rank approximation of the γ-adenosine triphosphate signal. Group analysis and regression on individual volunteers were performed to investigate quantitative concentration differences between different tissue types. Results: Differences in gray and white matter tissue 31P concentrations could be investigated for 12 different 31P resonances. In addition, the first highly resolved quantitative MRSI images measured at B0 = 9.4 Tesla of 31P detectable metabolites with high SNR could be presented. Conclusion: With an ultrahigh field strength B0 = 9.4 Tesla, 31P MRSI moves further toward quantitative metabolic imaging, and subtle differences in concentrations between different tissue types can be detected.