Interferon-beta-1a in relapsing-remitting multiple sclerosis: effect on hypointense lesion volume on T1 weighted images

Objective-Recently, a strong correlation between the increase in hypointens e lesion load on T1 weighted spin echo images, and the increase in disabili ty was reported. Although the effect of interferon-beta has been demonstrat ed both in reducing exacerbation rate, frequency of enhancing lesions, and accumulation of disease burden on T2 weighted images, the impact on the acc umulation of hypointense lesions has not yet been evaluated. The aims of th e present study were: (a) to assess for the first time the effect of interf eron-beta-1a on T1 weighted MRI hypointense lesion volume; and (b) to evalu ate the relation between changes on hypointense, hyperintense, and enhancin g lesion volume before and during interferon-beta-1a treatment in relapsing -remitting multiple sclerosis. Methods-After a baseline scan and 6 month pretreatment period, 67 patients with relapsing-remitting multiple sclerosis were treated with interferon-be ta-1a by subcutaneous injection three times a week during a 12 month treatm ent period. All patients had MRI every month during the 6 month pretreatmen t period and for the first 9 months of the treatment period. A final MRI wa s also performed at the end of the 12 month treatment period. Results-There was a significant increase in the mean hyperintense lesion vo lume during the pretreatment phase (6 months) and a slight decrease during the treatment period (12 months), whereas the hypointense lesion volume inc reased significantly before treatment and remained substantially stable dur ing treatment. There was a significant correlation between changes in hypoi ntense and hyperintense lesion volume during the observation period, but no t during treatment. The monthly mean volume of Gadolinium-DTPA enhancing le sions was significantly higher during the pretreatment than the treatment p eriod, and the enhancing lesion volume correlated with changes of hyperinte nse and hypointense lesion volumes only during the observation period. Conclusion-These data suggest that interferon-beta-1a has a stabilising eff ect on T1 weighted hypointense lesion volume.