Quantitative assessment of brain iron by R 2 * relaxometry in patients with clinically isolated syndrome and relapsing

Abstract

Background

Increased iron deposition has been implicated in the pathophysiology of multiple sclerosis (MS), based on visual analysis of signal reduction on T₂-weighted images. R₂* 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 R₂* relaxation rates and their correlations with age, disease duration, disability, T₂ lesion load, and normalized brain volumes.

Results

Basal ganglia R₂* 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 R₂* 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.

Keywords

3T MRI brain atrophy deep gray matter iron deposition multiple sclerosis R2* mapping

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Quantitative assessment of brain iron by R 2 * relaxometry in patients with clinically isolated syndrome and relapsing–remitting multiple sclerosis

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