Magnetic resonance imaging outcome of new enhancing lesions in relapsing-remitting multiple sclerosis patients treated with interferon beta(1a)

We investigated whether interferon-beta(1a) modifies the course of new enha ncing lesions in relapsing-remitting multiple sclerosis. Sixty-eight patien ts were studied by monthly magnetic resonance imaging (MRI) in a pretest-po sttest design including 6 months of observation and 6 months of treatment. We examined the course of new Gd-enhancing lesions on two consecutive scans during observation and during treatment. Lesions detected during treatment were also analyzed by MRI 1 year later for persistence of enhancement, per sistence of T2 hyperintensity, development of T1 hypointensity, or disappea rance. Among the enhancing lesions detected by observation and treatment MR I, respectively, Gd-enhancement persisted at 2 months in 20% and 3% (P < 0. 001), T2 hyperintensity persisted in 86% and 63% (P < 0.03), and T1 hypoint ensity developed in 49% and 15% (P < 0.01). Progression to TI hypointensity was significantly more frequent in larger lesions during both the observat ion and treatment periods (P < 0.01). No reenhancement of plaques was prese nt at I-year follow-up; a further reduction in T2 hyperintensity (63% vs. 3 9%) was observed while T1 hypointensity remained unchanged. Both the durati on of Gd enhancement and the short-term MRI course of new enhancing lesions benefited by treatment with recombinant interferon-beta(1a) treatment.