Neuroimaging Tests
MRI is the most important brain imaging test for epilepsy. It uses magnetic pulses to map the structure of the brain, providing a very detailed image. No radiation is given to the patient in an MRI. This test will not show epileptic activity, but may demonstrate a structural abnormality in brain, of a type likely to give rise to seizures.
MRIs can show new and old strokes, bleeding in or around the brain, inflammation from meningitis, abnormal blood vessels (arteriovenous malformations, cavernous malformations, aneurysms), sites of head trauma, brain infections or their aftermath, benign or malignant tumors, multiple sclerosis, birth malformations of brain (called dysplasias), and several other types of a structural problem. A condition of special interest for epilepsy is called "mesial temporal sclerosis."
This represents a scarring of the inner temporal lobe (hippocampus) of a type likely to occur with repeated seizures from the temporal lobe. It is a marker for a likely place where seizures originate. Not all MRIs are alike, having different degrees of detail, different techniques and different methods of highlighting certain desired features. In addition, MRIs (or the underlying conditions seen in them) can change over time. Therefore, MRIs sometimes bear repeating, even if a prior MRI was normal.