부산대학교 도서관

This thesis is based in four original articles and one review from the same research topic: the use of different magnetic resonance (MR) and electrophysiological techniques to evaluate and predict the clinical and cognitive disability in patients with multiple sclerosis (MS). First, the radiological behaviour and clinical meaning of lesions with hipointense rim on T2 weighted sequences and lesions with ring enhancement on T1 were evaluated. The presence of ring enhancement increases the risk of disability worsening. On the second article, the corpus callosum was evaluated through electrophysiological and MR techniques to understand the role of this structure on physical and cognitive dysfunction in MS patients. The structure and function of the corpus callosum is impaired in MS and relates to worse cognitive performance in memory and executive tests. Third, we used several advanced MR techniques to evaluate the integrity of brain tissue, both in white matter and grey matter, in MS and their relationship with cognitive functions. The microstructural integrity is widespread impaired although the cognitive performance relates to the damage of specific regions. The impairment of white matter microstructural integrity and the presence of lesions are the main factors explaining the cognitive impairment in patients. Finally, the capacity of markers of demyelination, axonal damage and astrogliosis to predict the evolution of disabilty and brain atrophy along four years was investigated. This work shows that astrogliosis and axonal damage are cardinal events leading to disesase evolution. The ratio of myoinositol and N-acetylaspartate obtained through spectroscopy is a robust predictor of disability and brain atrophy progression. These works have improved the knowledge on the physiopathological events underlying disability in multiple sclerosis and can be useful in the search of biomarkers that predict disease evolution.