New hypointense lesions on MRI in relapsing-remitting multiple sclerosis patients

Background: Preliminary observational studies with multiple sclerosis (MS) patients have reported strong correlations between an increase in hypointen se lesion load (black holes) on T1-weighted spin echo images, and an increa se in disability. Objective: We assessed the relationship of hypointense le sions to the clinical course of disease among 50 relapsing-remitting MS pat ients in the controlled setting of a randomized clinical trial. Methods: Fi fty patients with relapsing-remitting disease were enrolled in a randomized double-blind two-arm (cladribine vs, placebo) clinical trial of 1-year dur ation. All patients had monthly clinical evaluations and MRIs over the cour se of the trial. Multivariate techniques were used to identify predictors o f clinical severity from information on exacerbations, MRIs, baseline clini cal parameters, and demographics. Results: At baseline, clinical severity i s weakly related to counts of black holes, with rank correlations between c ounts and clinical scores (EDSS and SNRS) of absolute magnitude 0.3. Rates of appearance of new black holes over the course of the trial are higher fo r patients with more severe disease at baseline (EDSS greater than or equal to 4) than for the less severe patients. Changes in clinical severity over the course of the trial are best predicted by baseline neurologic scores a nd numbers of exacerbations, with black holes adding no further improvement in prediction. Conclusions: Numbers of exacerbations seem more critical to short-term clinical outcomes in relapsing-remitting MS, as reflected by pa tients' clinical scores, rather than black holes. Various imaging methods a nd MRI indices capture complementary information relating to MS disease pro cesses. The determination of which processes are affected by different drug s should lead to more effective treatment of MS patients. Copyright (C) 200 0 S. Karger AG, Basel.