Quantitative assessment of brain iron by R2* relaxometry in patients with clinically isolated syndrome and relapsing-remitting multiple sclerosis

Background Increased iron deposition has been implicated in the pathophysiology of multiple sclerosis (MS), based on visual analysis of signal reduction on T-2-weighted images. R-2* relaxometry allows to assess brain iron accumulation quantitatively. Objective To investigate regional brain iron deposition in patients with a clinically isolated syndrome (CIS) or relapsing-remitting MS (RRMS) and its associations with demographical, clinical, and conventional magnetic resonance imaging (MRI) parameters. Methods We studied 69 patients (CIS, n = 32; RRMS, n = 37) with 3T MRI and analyzed regional R-2* relaxation rates and their correlations with age, disease duration, disability, T-2 lesion load, and normalized brain volumes. Results Basal ganglia R-2* relaxation rates increased in parallel with age (r = 0.3-0.6; P < 0.01) and were significantly higher in RRMS than in CIS (P < 0.05). Using multivariate linear regression analysis, the rate of putaminal iron deposition was independently predicted by the patients' age, disease duration, and gray matter atrophy. Conclusions Quantitative assessment by R-2* relaxometry suggests increased iron deposition in the basal ganglia of MS patients, which is associated with disease duration and brain atrophy. This technique together with long-term follow-up thus appears suited to clarify whether regional iron accumulation contributes to MS morbidity or merely reflects an epiphenomenon. Multiple Sclerosis 2009; 15: 1048-1054. http://msj.sagepub.com