In vivo Microscopic Imaging of Multiple Sclerosis with High Field MRI

Abstract

Acquiring the ability to visualize areas of demyelination in the brains of patients with multiple sclerosis (MS) by magnetic resonance imaging (MRI) marked a turning point in the diagnosis of this disease. MRI has enabled the systematic examination of distribution and time-dependent characteristics that lead to the development of long-term clinical disability in MS patients. An understanding of this series of events permits a qualitative and quantitative evaluation by MRI of the effects of therapeutic strategies [1]. Many of the early MRI studies examined the sensitivity of the MRI technique in detecting lesions of MS [2] only. The longterm natural history of MS has also been studied by MRI. It has long been evident that relapses of MS as evident on MRI occur regularly, but that only a small fraction of such exacerbations manifest clinically. Therefore, MRI is essential to directly monitor the progression of disease. Drugs under investigation for their efficacy have been examined for their ability to modify the MRI profile [3], and a favorable effect visible on MRI has become an expected effect of such drugs. However, a disparity has been identified in numerous studies and over the last decade: it has become increasingly evident that lesions seen on conventional MRI may correlate poorly with clinical disability. Therefore, there remain significant imaging challenges to better characterize MS patients by MRI. Defining the white matter lesions is not the complete story.