Radiologically Isolated Syndrome: An Overview

The use of brain magnetic resonance imaging (MRI) for evaluation of neurological disorders has increased in the past two decades. This has led to an increased detection of incidental findings on brain MRI. The most common of these asymptomatic abnormalities are white matter lesions that are interpreted as demyelinating based on radiological criteria. However, in the absence of associated clinical symptoms suggestive of multiple sclerosis (MS), a definite diagnosis of MS cannot be made in patients with these incidental white matter lesions. These patients are now diagnosed as radiologically isolated syndrome (RIS). The natural history and clinical approach to patients with RIS are reviewed in this article.