ABSTRACT
Interferon-β (IFN-β) is an effective disease-modifying treatment for patients with relapsing-remitting and secondary progressive multiple sclerosis (RRMS and SPMS).1-4 Perhaps the most impressive therapeutic benefit of this treatment is the dramatic reduction in number of new gadolinium-enhanced and T2-weighted lesions.1-6 However, lesions imaged with T2-weighted sequences do not reliably distinguish reversible oedema and inflammation from irreversible demyelination and axonal loss. Thus, it was unknown whether the effects of IFN-β reflected a benefit on reversible or irreversible tissue damage. In a preliminary effort to determine whether IFN-β could reduce the change in a putative marker of irreversible tissue damage, we studied the magnetization transfer ratio (MTR) of new gadolinium-enhanced lesions that became visible before and after initiating treatment with IFN-β-1a (6.0 MIU intramuscularly each week).7 We found that the MTR was similar in new lesions that became visible before and during treatment. Richert et al8 have independently reported that serial whole-brain MTRs were similar before and after initiating treatment with IFN-β-1b.
