MRI was first introduced in the United States in the early 1980s, further revolutionizing the practice of neurology and neurosurgery.It is also the most important neuroimaging test in epilepsy, because it shows excellent detail of the brain’s structure, even more than CT.
The MRI does not use x-rays, but rather uses a powerful magnet that changes the spin on atomic particles that are normally part of the body, and then measures the changes in the magnetic field as the particles resume their previous course. The patient does not feel anything. The images are a remarkably accurate representation of the brain’s structure. MRI is extremely helpful for identifying brain scar tissue, areas of abnormal brain development (dysplasia), small brain tumors, blood vessel abnormalities, and changes in the brain’s white matter.
Although the MRI is safe and painless, most MRI machines require that the person’s head and upper body be placed in a very confined space. People with claustrophobia (fear of small places), and many who never knew they were claustrophobic, may become frightened and uncooperative when they see the confinement required for the test. Medications for relaxation can be given (children often require medications to put them to sleep), or a newer type of MRI machine ("open MRI"), which is not so confining, can be used. At present, however, the scans from open MRIs are not as detailed as those of the regular MRIs, and this difference can be important for patients being considered for epilepsy surgery. Also, patients will notice that MRI machines emit loud noises, and the MRI technician will often offer the patient earplugs for their comfort.