Imaging Neuroinflammation in Epilepsy With Ferumoxytol MRI

The investigators plan to study inflammation in the brain (neuroinflammation) in human patients with epilepsy using a novel, non-invasive technique that has been proven successful in humans with other neuroinflammatory diseases. This technique uses ferumoxytol, a drug with minimal side effects that is FDA-approved for the treatment of iron deficiency anemia, as the contrast agent in magnetic resonance imaging (MRI). The study will recruit epilepsy patients who are admitted to Dartmouth-Hitchcock Medical Center (DHMC) for video-electroencephalography (video-EEG) monitoring in order to evaluate their candidacy for curative brain surgery. During the hospital stay and after informed consent, the patient will receive a standard-dose intravenous injection of ferumoxytol, and undergo one session of MRI at 24-48 hours after the injection. The patient will also undergo a separate "baseline" MRI session (if not already done at DHMC) at admission or at more than four weeks after the injection but before any brain surgery. Brain regions that preferentially uptake ferumoxytol are localized by subtracting the post-injection MRI session from the "baseline" MRI session. The investigators will investigate whether these regions overlap with the epileptogenic focus, namely the region that generates epilepsy and is localized by video-EEG and other diagnostic measures. Lastly, for those patient participants who thereafter undergo brain surgery, DHMC neuropathologists will use special stains to detect and quantify neuroinflammation in brain tissue removed, and the results will serve as the reference for the investigators to measure the sensitivity and specificity of ferumoxytol-based MRI in detecting neuroinflammation.