The only certain measure of the effectiveness of multiple sclerosis therapy is cerebrospinal neurofilament level—NO

There have been a number of attempts to use the presence or absence of evidence of new disease activity by magnetic resonance image (MRI) scanning as a prognostic tool in relation to future acquisition of disability. Several groups involved in such studies in Barcelona1,2 and in Cleveland3 have assessed evidence of new T2 lesions on annual MRI scanning as an indicator of adequate/inadequate disease control by a disease-modifying therapy. As pointed out in a previous “Commentary”, both the sensitivity and specificity of these indices are relatively poor; an attempt to refine them does not seem to be, to this observer, any significant advance.4 Of course it is natural to use evidence of accrual of new T2 lesions on an annual scan as being indicative that a particular therapy is not achieving adequate disease suppression. The problem is of course, as has been previously discussed, MRI scanning as used routinely on a 1.5 Tesla scanner is not a sufficiently sensitive tool to detect either grey matter disease or diffuse white matter disease.5 Basically MRI scanners and sequences that we use in daily life are blind to at least 50% of ongoing disease activity. In order to address this deficiency, quantitative measures of cerebral atrophy have been introduced in order to monitor the effects of the hidden grey matter disease.6 Whether these techniques can be applied in general neurological practice and provide a read-out which can be understood by neurologists is yet to be determined. It is also necessary to demonstrate whether reducing the rate of Multiple Sclerosis Journal