MRI (Magnetic Resonance Imaging)

The information provided is specific to investigating epilepsy, therefore imaging of the brain is only discussed.


Using strong magnetic fields and non ionizing radiation MRI scanners are able to produce the best images of the contrast between the different soft tissues of the body. This makes it particularly useful when imaging the brain as well as safe. 

The procedure involves laying still in the MRI machine often for long periods in a tight space, because of this people with claustrophobia, even mild forms have difficulty with this procedure. 

Once on the MRI table an apparatus is place around the head, you will be given ear plugs to dim the loud noise the equipment makes and a call button to alert staff. 

Recommendations for those nervous about MRI include; 

  • Visiting the MRI room before the procedure, 
  • Visualization techniques, 
  • Sedatives and anti anxiety medications, 
  • General Anesthesia may be necessary, usually for babies and small children. 

A contrast agent may be required to enhance the appearance of blood vessels, tumors and inflammation. 

It is administered intravenously through a catheter (venous cannula) which is placed into a vein, usually in the arm or hand. 

Once the MRI is complete the catheter is removed. 

Since MRI uses strong magnetic fields and radio pulses there is the possibility of disturbing metal implants therefore, the presence of any metal in the body needs to be reported to the technician prior to entering the MRI room. 

Such implants that can cause harm are cardiac pacemakers, cochlear implants, vagus nerve stimulators, and some indwelling medication pumps. Other forms of metal in the body that may cause harm include metal fragments in the eyes, some cerebral aneurysm clips and metal hardware. 

A questionnaire is used by the MRI staff to screen for any metals prior to the procedure taking place. Some implants have been approved by the FDA as MRI compatible, if you have any form of implant bring the product information with you, the technician will be able to check for compatibility. 

MRI is done as an outpatient visit.

University of Southern California University of Southern California