The purpose of this study is to determine the diagnostic accuracy of ferumoxytol-enhanced MRI in detecting lymph nodes that have been invaded by tumor cells in patients with colorectal cancer.

This study will investigate the accuracy of ferumoxytol-enhanced MRI in detecting lymph nodes that have been invaded by tumor cells in patients with colorectal cancer. This study will be performed in addition to any ongoing routine care and will not serve as a substitute for any imaging tests that would be routinely performed prior to surgery.

Inclusion Criteria:

• Patients 18 years of age or older with histologically confirmed colorectal cancer
• Planned for surgical resection of tumor

Exclusion Criteria:

• Contraindications for MRI
• Contraindication or known allergy to ferumoxytol or parental iron products (e.g. iron sucrose, iron dextran, etc.)
• Planned chemotherapy or radiation treatment prior to surgical resection of primary tumor
• Uncontrolled serious medical illness
• Unable or unwilling to give informed consent
• Pregnancy
• Breastfeeding women
• Clinically documented or known risk of primary or secondary iron overloading including history of thalassemia, sickle cell anemia, hereditary hemochromatosis or first-degree relative with known hemochromatosis, multiple transfusions for any reason within the past 5 years, or use of over-the-counter ferrous sulfate without the supervision of his/her doctor