Post-cardiac surgery patients and patients with the following medical devices can be safely examined with MRI:

* Surgical clips or sutures
* Artificial joints
* Staples
* Cardiac valve replacements
* Disconnected medication pumps
* Vena cava filters (after 6 weeks for certain types)
* Brain shunt tubes for hydrocephalus
* Metal stents

Some conditions may make a MRI examination inadvisable. Tell your doctor if you have any of the following conditions:

* Heart pacemaker
* Cerebral aneurysm clip (metal clip on a blood vessel in the brain)
* Pregnancy
* Implanted insulin pump (for treatment of diabetes), narcotics pump (for pain medication), or implanted nerve stimulators ("TENS") for back pain
* Metal in the eye or eye socket
* Cochlear (ear) implant for hearing impairment
* Implanted spine stabilization rods
* Severe lung disease (such as tracheomalacia or bronchopulmonary dysplasia)
* Gastroesophageal reflux
* Weight of more than 300 pounds
* Inability to lie on back for 30 to 60 minutes
* Claustrophobia (fear of closed or narrow spaces).