SECONDARY PROGRESSIVE MULTIPLE-SCLEROSIS - THE RELATIONSHIP BETWEEN SHORT-TERM MRI ACTIVITY AND CLINICAL-FEATURES

We report the findings in 60 patients with secondary progressive multi ple sclerosis who had monthly brain MRI studies for 4 months (one base line and three follow-up scans). The purpose was to define the short-t erm MRI natural history in a large cohort with secondary progressive d isease and to ascertain its relationship with other clinical and MRI f eatures. The patients were participating in either a natural history s tudy or the placebo arm or non-treatment phase of a therapeutic trial. The cohort had clinical features typical of secondary progressive dis ease: thus, all had moderate or severe locomotor disabilities [Expande d Disability Status Scale (EDSS), score 3.5-8], with a median disease duration of 12 years. There was equal representation of males and fema les. During the 3 months of follow-up there was a total of 362 new enh ancing lesions seen in 42 patients, and there were 24 relapses in 20 p atients. There was no correlation between new enhancing lesions and ag e at study entry age of disease onset, gender disease duration or EDSS , but there was a strong correlation with the number of enhancing lesi ons on the baseline scan (r = 0.65, P < 0.0001) and subsequent activit y There was a non-significant trend for higher numbers of new, enhanci ng lesions in those having relapses during the 3 months of scanning (P = 0.14) or in the preceding 6 months (P = 0.06). The 34 patients who did not relapse in either period had significantly fewer new active le sions (P = 0.02) than those who relapsed at some stage during the 9 mo nths. Nevertheless, considerable activity was seen in rite non-relapsi ng cohorts: there was a mean of 3.5 (median 2) new enhancing lesions i n those not relapsing during the 3 month study, and 5.5 (median 2) in those not relapsing in the previous 6 months. We conclude that short-t erm MRI activity is generally high in secondary progressive disease, c onfirming a useful role for the technique in exploratory trials. Furth er work should concentrate on elucidating the mechanisms of secondary progression by longer term follow-up studies of larger cohorts rising multiple MRI and clinical measurements.