The definition of non-responder to multiple sclerosis treatment: neuroimaging markers.

MRI is the main paraclinical tool used both to diagnose multiple sclerosis (MS) and to evaluate the efficacy of experimental treatments in phase II and III clinical trials. In the latter context, a major issue is represented by the weak correlations found between clinical and MRI aspects in the case of established MS, which are particularly evident when individual patients are considered. As a consequence, the definition of response to MS treatment, when based upon MRI aspects, remains a challenging task. Although the use of MRI-derived quantities to define treatment options and strategies at an individual patient level is supported by recent evidence, only the integration of clinical and MRI data can be considered a reliable approach for the work-up of patients undergoing disease-modifying treatments.