Inclusion Criteria:

- ≤ 18 years of age

- radiological (presumptive) or established (proven) histological diagnosis of a brain
tumor or lesion

- previously untreated patients must have a measureable lesion on an imaging study

- Baseline MRI studies for patients receiving ferumoxytol must be performed within 6
weeks of study entry

- Patients undergoing active treatment, or who have completed treatment, will have
radiographic abnormalities that may or may not be recurrent tumor

- patients requiring surgical intervention for diagnostic and/or therapeutic purposes
as necessary for their disease are eligible

- Patients may have had prior therapy for the primary brain tumor, including surgery,
radiotherapy or chemotherapy

- agree to be followed for up to 6 weeks after the final infusion of ferumoxytol

- patients, or their legal guardians, must sign a written informed consent and HIPAA
authorization in accordance with institutional guidelines

- Sexually active women of child-bearing potential and men must agree to use adequate
contraception (hormonal or barrier method of birth control;abstinence) prior to study
treatment and for the duration of study treatment

Exclusion Criteria:

- Patients with clinically significant signs of uncal herniation, such as acute
pupillary enlargement, rapidly developing motor changes (over hours), or rapidly
decreasing level of consciousness

- Patients with known allergic or hypersensitivity reactions to parenteral
iron,parenteral dextran, parenteral iron-dextran, or parenteral iron-polysaccharide
preparations (Ferumoxytol Investigator's Drug Brochure, 2009)

- Patients who are pregnant, lactating, or who suspect they might be pregnant

- Patients with known liver function insufficiency (AST and/or ALT greater than 2.5x
upper limits of normal) or stage IV (GFR 15-29 mL/min/1.73 m2) or stage V (GFR <15
mL/min/1.73 m2) renal insufficiency

- Subjects who have a contraindication for MRI: metal in their bodies (a cardiac
pacemaker or other incompatible device), are severely agitated, or have an allergy to
GBCA

- Subjects with known hepatic insufficiency or cirrhosis

- HIV-positive patients on combination antiretroviral therapy are ineligible because of
the potential for pharmacokinetic interactions with ferumoxytol