- Magnetic resonance imaging. This procedure is done after implantation of the stimulators to verify position of the electrodes. MRI uses a magnetic field and radio waves to produce images of the brain. The patient lies on a table that is moved into the scanner (a narrow cylinder), wearing earplugs to muffle loud knocking and thumping sounds that occur during the scanning process. The procedure usually lasts about 45 to 90 minutes, during which the patient is asked to lie still for up to 15 minutes at a time.