Grant: Operating Grant

Multiple sclerosis (MS) is the most common neurological disorder affecting young adults in Canada, with about 1000 new cases diagnosed in Canada each year. Current treatments can reduce the number of relapses and slow the disease, but there is no cure. While magnetic resonance images can show MS lesions in the white matter of the brain, current techniques do not show many of the lesions in the grey matter that covers the surface of the brain (cerebral cortex). The ability to see MS lesions involving the grey matter is arguably the greatest challenge at present for the clinical application of MRI to multiple sclerosis (MS). A number of autopsy studies have demonstrated that MS lesions involving the cerebral cortex are common in MS, despite the fact that these lesions do not show up on standard MRI examinations. We have developed methods that use advanced image processing of magnetization transfer ratio (MTR) images to address this unmet need at clinically-accessible field strengths (i.e., 3 Tesla or less) by calculating the MTR on a calculated surface mid-way between the outside of the brain and the junction of the cortex and the white matter just below the cortex. We propose to validate our clinically feasible method against images obtained at the ultra-high field strength of 7 Tesla. Scanning at 7T is not generally accessible in the clinic, but appears to provide the best available technique for detection of cortical lesions in MS patients. We then will be in a position to use our validated methods to answer basic questions about the development of cortical lesions in MS, such as when in the course of the disease they develop, how they relate to physical and cognitive disability, and at what rate do they develop in different phases of the disease. Answers to these questions are vital to increase our understanding of cortical lesions, and to guide development of new therapies that are effective against this component of MS pathology.