BLOOD-BRAIN-BARRIER DISRUPTION ON CONTRAST-ENHANCED MRI IN PATIENTS WITH MILD RELAPSING-REMITTING MULTIPLE-SCLEROSIS - RELATIONSHIP TO COURSE, GENDER, AND AGE

MRI has provided insight into the pathophysiology and course of MS, pa rticularly through the use of a paramagnetic contrast agent that allow s visualization of blood-brain barrier (BBB) breakdown. Neither the ov erall frequency of BBB breakdown in MS patients nor the characteristic s associated with BBB breakdown in MS are known. We studied 68 relapsi ng-remitting RIS (RRMS) patients with three monthly MRIs to examine th ese questions. Seventy-eight percent of the RRMS patients studied had evidence of BBB breakdown on at least one MRI. While there was a great deal of variability among patients in terms of mean enhancing lesion frequency, BBB breakdown was associated with younger age at onset of d isease, measured by age at first symptom or age at diagnosis, and more severe disease as measured by Expanded Disability Status Scale scores equal to or greater than 4.0. We found no relationship between BBB br eakdown and duration of disease or gender. We conclude that BBB breakd own is a relatively common phenomenon in RRMS patients and may be most commonly found in patients with more aggressive disease and younger o nset. These findings have implications for clinical trials that use MR I as an outcome measure.