Quantitative methods in magnetization transfer and chemical exchange saturation transfer at 7T

Ultra-High field (7T) MRI provides high sensitivity which allows for new qualitative and quantitative methodologies to be developed, that provide clinically useful information. The work presented in this thesis is focussed on developing a quick and reliable quantitative MT and CEST methodology, taking account of the difficulties encountered at high field. The method developed here has been tested on various studies, in both healthy and diseased brain, in an effort to aid the understanding of myelination in the human brain. The work in this thesis uses the quantitative measure of MT as a marker for myelination, and it shows strong correlations between MT-based myelination and functional connectivity, as well as very strong correlation between MT and NOE. These findings showcase the potential of NOE as a myelin marker as well, as long as the MT vs. NOE relationship remains the same in pathology. Myelination is investigated (via MT and NOE) in Multiple Sclerosis (MS) and Glioma, showing a strong coupling between the two exists even in pathology. Amide Proton Transfer (APT) is also investigated in Glioma, showing similar trends to MT and NOE. High resolution anatomical images can provide valuable information on the extend of the pathology, but quantitative information of the NMR properties of tissue (like MT, NOE and APT) has the potential to detect earlier abnormalities, and give a quantitative measure of healing or degeneration caused by pathology