Metabolite Mapping of the Human Brain at 9.4T

Abstract

1H MRSI is a powerful technique for mapping the spatial distribution of metabolites in the human body, essentially, allowing researchers and clinicians to perform virtual biopsy in a non-invasive manner. These metabolite maps can provide sensitive markers of disease and injury, or can be used to provide insight into the neurochemical processes of the brain. 1H MRSI, therefore, has great potential for clinical diagnostics, as well as biomedical and neuroscience research.

Perhaps the greatest hindrance to the application of MRSI in research and clinics is the time-consuming nature of such experiments. Even though acquiring reliable MRSI data with high spatial resolution and more tissue coverage is desirable for answering many neuroscientific or clinical questions, this comes at the price of even more prolonged scan times.

Compared to lower field strengths, MRSI at ultra-high field strengths has the advantage of higher signal-to-noise-ratio (SNR) as well as increased spectral resolution. These advantages enable the quantification of more metabolites with greater accuracy in the brain. Furthermore, some of the additional SNR can be traded off for shorter scan times through acceleration techniques. However, to be able to benefit from these advantages at ultra-high fields, there are many technical challenges that should be overcome.

The focus of this thesis is, therefore, to develop acquisition sequences, image reconstruction methods, and acceleration techniques to overcome these challenges and enable high resolution whole brain metabolic imaging in the human brain by magnetic resonance spectroscopic imaging at 9.4T. In doing so, we hope to bring metabolic imaging through 1H MRSI one step closer to clinical practice.