2. Clinical MS relapse and/or new MRI lesion(s) within the preceding 2 years
3. Positive pregnancy test
4. Gadolinium contrast allergy
5. Acute or chronic kidney disease with eGFR \<30 ml/min/1.73m2
6. Pacemaker or other MRI contraindications per American College of Radiology guidelines
7. Intravenous iron sensitivity
8. Serum ferritin and transferrin saturation above age-adjusted upper limit of normal (if serum ferritin is above normal, but transferrin saturation is normal, the subject is NOT excluded)