Development of hypointense lesions on T-1-weighted spin-echo magnetic resonance images in multiple sclerosis - Relation to inflammatory activity

Objective: To evaluate whether degree of inflammatory activity in multiple sclerosis, expressed by frequency of gadolinium enhancement, has prognostic value for development of hypointense lesions on T-1-weighted spin-echo mag netic resonance images, a putative marker of tissue destruction. Design: Cohort design with long-term follow-up. Thirty-eight eight patients with multiple sclerosis who in the past had been monitored with monthly ga dolinium-enhanced magnetic resonance imaging for a median period of 10 mont hs (range, 6-12 months) were reexamined after a median period of 40.5 month s (range, 33-80 months). Setting: Magnetic Resonance Center for Multiple Sclerosis Research, Amsterd am, the Netherlands, referral center. Main Outcome Measures: The low enhancing lesion rate (median number of gado linium-enhancing lesions per monthly scan) during initial monthly follow-up ; hypointense T-1 and hyperintense T-2 lesion load at first and last visit. Results: The number of enhancing lesions on entry scan correlated with the new enhancing lesions rate (r = 0.64; P<.001, Spearman rank correlation coe fficient). The new enhancing lesion rate correlated with yearly increase in T-1 lesions rate; P<.001, Spearman rank correlation coefficient) and T-2 ( r = 0.47; P<.01, Spearman rank correlation coefficient) lesion load, initia l T-1 lesion load correlated more strongly with yearly increase in T-1 lesi on load (r = 0.68; P<.01, Spearman rank correlation coefficient). Conclusions: Degree of inflammatory activity only partially predicted incre ase in T-1 (and T-2) lesion load at long-term follow-up. Initial T-1 lesion load strongly contributed to subsequent increase in hypointense T-1 lesion load, suggesting that there is a subpopulation of patients with multiple s clerosis who are prone to develop destructive lesions.