MRI features associated with rapid disease activity in clinically isolated syndrome patients at high risk for multiple sclerosis.

Clinically isolated syndrome (CIS) is a central nervous system inflammatory and demyelinating event that lasts at least 24 h and can represent the first episode of relapsing-remitting multiple sclerosis. MRI is an important imaging tool in the diagnosis and longitudinal monitoring of CIS progression. Accurate differential diagnosis of high-risk versus low-risk CIS is important because high-risk CIS patients could be treated early. Although a few studies have previously characterized CIS and explored possible imaging predictors of CIS conversion to MS, it remains unclear which amongst the commonly measured MRI features, if any, are good predictors of rapid disease progression in CIS patients. The goal of this review paper is to identify MRI features in high-risk CIS patients that are associated with rapid disease activity within 5 years as measured by clinical disability.