Longitudinal Follow-up of a Cohort of Patients with Incidental Abnormal Magnetic Resonance Imaging Findings at Presentation and Their Risk of Developing Multiple Sclerosis.

Background: Magnetic resonance imaging (MRI) is widely used in clinical practice, and "abnormal brain MRI" findings often prompt assessment for multiple sclerosis (MS), even when there are no symptoms suggestive of the disease. Despite several studies involving individuals with "radiologically isolated syndrome" (RIS), little is known about what factors might predict future development of MS. The objective of this study was to longitudinally evaluate clinical and MRI characteristics of people who presented to an MS clinic because of incidental abnormal MRI findings but did not have typical symptoms of MS, in order to assess risk factors for developing MS.

Methods: Thirty consecutive patients presenting to an MS clinic for evaluation of abnormal MRI findings were enrolled in the study. Clinical and paraclinical data, including MRI results, were reviewed. Magnetic resonance imaging findings of T2 hyperintensities measuring more than 3 mm in diameter and fulfilling at least three out of four Barkhof criteria, with or without gadolinium-enhancing lesions, were considered to be suggestive of MS.

Results: The median follow-up time was 5.5 years. No participants without MRI findings suggestive of MS were diagnosed with MS (P = .005). Fifteen participants had MRI findings suggestive of MS. Seven of the 15 (47%) were diagnosed with MS on follow-up. Cerebrospinal fluid (CSF) testing results were available for 15 participants. Abnormal results were found in six participants, of whom five (83%) also had MRI findings suggestive of MS. Only two of the nine (22%) participants with normal CSF results (P = .04) had MRI findings suggestive of MS.

Conclusions: In our cohort, none of the participants without MRI findings suggestive of MS developed MS. The participants with MRI findings suggestive of MS were more likely to develop symptoms and MRI changes typical of MS on follow-up.