Contrast-enhanced magnetic resonance activity in relapsing remitting multiple sclerosis patients: a short term natural history study

Magnetic resonance imaging (MRI) has been used to study the history of mult iple sclerosis (MS). We analyze the relationship between MRI activity in th e first scan compared to the subsequent five scans, and we evaluate whether a shorter observation period of 3 months may predict the subsequent 3 mont hs. Monthly enhanced MRI was Performed in 103 relapsing remitting (RR) MS p atients for 6 months. Thirty-five per cent of patients had on inactive scan on the initial examination. More than 80% of them developed MRI activity d uring the following 5 months. Eighteen per cent of patients had three conse cutive inactive scans; 65% of them had at least one active scan on the subs equent 3 monthly MRI's. The relationship between the first scan and oil sub sequent scans demonstrates a clear weakening over time. Eighty-two per cent of patients had at least one active scan during the initial 3 consecutive months, the chance of becoming inactive decreased from 23% to 0% over the s ubsequent 3 months, according with the mean number of enhancing lesions dur ing the first 3 months. These results suggest that neither a single scan no r a short baseline of 3 months may adequately describe the natural history of disease in on individual RRMS patient.