Determinants of brain iron in multiple sclerosis: a quantitative 3T MRI study

Area of Science:

• Neuroimaging
• Neurology
• Biomarkers

Background:

• Abnormal cerebral iron deposition is implicated in chronic neurological disorders like multiple sclerosis (MS).
• R2* relaxometry quantifies brain iron accumulation, validated in postmortem studies.
• Assessing brain iron levels in MS stages can elucidate disease mechanisms.

Purpose of the Study:

• To evaluate brain iron levels in different stages of multiple sclerosis (MS) and healthy controls (HC) using R2* relaxometry.
• To determine the relationship between brain iron deposition and demographic, clinical, neuropsychological, and imaging variables in MS.
• To investigate whether iron accumulation precedes or follows MS development.

Main Methods:

• 113 patients (35 clinically isolated syndrome [CIS], 78 MS) and 35 HC underwent 3 Tesla MRI.
• Automated, regional R2* rates quantified iron deposition in subcortical gray matter structures.
• Clinical and neuropsychological examinations were performed.

Main Results:

• Basal ganglia (BG) R2* levels were significantly higher in MS patients compared to CIS and HC.
• BG R2* levels correlated with age, disease duration, disability (Expanded Disability Status Scale), and processing speed.
• Gray matter atrophy, age, and T2 lesion load were independent predictors of BG R2* levels.

Conclusions:

• Basal ganglia iron accumulation in MS increases with disease progression and correlates with morphologic brain damage.
• Iron deposition in MS appears to be an epiphenomenon, a consequence of disease-related brain damage.
• The lack of increased iron in CIS suggests iron accumulation does not precede MS onset.