As a test that evaluates the structure of the human living brain, Magnetic Resonance Imaging (MRI) has virtually replaced Computed Tomography (CT). MRI has a higher resolution than CT. Often, a MRI scan shows subtle abnormalities that a CT scan will miss. It has proven to be an invaluable tool in the evaluation of patients with epilepsy. It is a noninvasive test that does not use x-rays or any kind of harmful radiation. Instead, MRI relies on strong magnetic fields in order to produce brain images.