Improving Aspects of In-Vivo Magnetic Resonance Spectroscopy Metabolite and Fat Quantification

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Magnetic Resonance Spectroscopy (MRS) is a non-invasive (does not require a surgical procedure) methodology that can measure levels of relevant body and brain substances involved in metabolism (metabolites). It uses an MRI (magnetic resonance imaging) unit. The objective of the research program is to improve MRS quantification of relevant brain metabolites and body fat composition at the human field strength of 3 T and the stronger magnetic field strength of 9.4 T, often used in pre-clinical research on animals. Both MRI units are at the Cross Cancer Institute (Edmonton's cancer hospital). MRS techniques that enable improved determination of unsaturated fat (type of fat with at least one double bond in its structure) and omega-3 fat levels in adipose tissue, such as bone marrow and abdominal fat tissue will be developed for human (3 T) and animal studies (9.4 T). The measures are relevant because levels of fat unsaturation have been shown to change due to diseases such as osteoporosis, obesity, liver disease and cancer. In addition, possible changes in omega-3 content of breast tissue may be associated with breast cancer risk. Levels of omega-3 fatty acids are low in body fat tissue (about 1 2 %) and therefore, its detection with MRS is difficult, a challenge we aim to overcome. Our long term goals involve applying the developed methods to correlate fat composition with cancer risk, tumour types and treatment response in humans and animal (rodent) models of disease. In addition, MRS techniques that allow for improved measures of brain metabolism will be designed and implemented at 9.4 T. Specifically, improved quantification of dynamic measures (changes that occur during metabolism) of glutamate, glutamine and GABA (relevant brain metabolites) will be achieved to improve metabolism assessment in rodents. Our long term goals involve utilizing the developed methodologies to improve our understanding of brain tumour metabolism (in rodent models) and its response to treatment. Another long term goal is to investigate correlations between measures obtained with MRS and PET (Positron Emission Tomography), an imaging methodology that uses radioactive tracers. Knowledge obtained from the animal studies can be translated to human studies on the new PET/MRI unit at the Cross Cancer Institute. The developed techniques will also be of benefit to other MRS studies being conducted at 3 T and at 9.4 T in Canada, where brain metabolism or fat levels are being assessed. The methods will provide the means to address metabolite and fat quantification challenges encountered with MRS.