Figure 2.

Inflammatory activity in multiple sclerosis (MS) may be detected clinically and/or radiologically. (A) The pre-symptomatic phase of the disease is defined by radiologically apparent relapses in the absence of clinical symptoms. (B) Following the first symptomatic demyelinating event, clinical and radiological relapses continue to occur. (C) Secondary progressive (SP) MS is defined by irreversible accumulation of disability due to chronic axonal loss which associates with ongoing brain atrophy and minimal inflammatory change on magnetic resonance imaging.