MRI Patient Safety
MRI is a safe, painless, and well established medical imaging examination. It has been performed on millions of people worldwide. However, due to the interaction of high field strength magnets and certain metallic objects, some patients cannot safely undergo MRI. These MRI safety concerns apply equally to persons who may simply accompany patients into the MRI scan room. Please consult the following list to see if you might have any potential MRI safety concerns. If so, please inform our staff well before your scheduled examination time. We will be happy to speak with you at 518-438-0600.
Electronically, magnetically, or mechanically activated implants
- Cardiac pacemakers (including patients with indwelling electrodes or wire leads even if the pacemaker box itself has been removed)
- Implantable cardiac defibrillators
- Cochlear (inner ear) implants
- Neurostimulators (e.g., dorsal column stimulators)
- Bone growth stimulators
- Implantable electronic drug infusion pumps
- Certain magnetically activated dental implants, magnetic sphincters, and the like
Cerebral aneurysm clips
There are many types of cerebral aneurysm clips. Some of these clips may be displaced or rotated by the magnetic field used in MRI. Our policy at Albany Advanced Imaging is to decline to perform MRI examinations on any and all patients with cerebral aneurysm clips.
Heart valve prostheses
Most types of heart valve prostheses (artificial heart valves) are not affected by MRI. However, a few older types of artificial valves are not allowed. If you have a cardiac valve replacement, we must have adequate documentation of the exact type of prosthesis before the MRI examination can be performed. Acceptable forms of documentation include the operative note from the original surgery, a detailed letter from the cardiac surgeon who inserted the valve, or a wallet card from the valve manufacturer. Since it may take some time to obtain this documentation, please try to have this important matter in order before your scheduled examination time.
Intravascular coils, filters, and stents
A few types of metallic coils, filters, and stents may move in the magnetic field used for MRI examination. However, all of these devices become tightly bound to the wall of the artery or vein within six weeks of insertion. Therefore, it is the policy of Albany Advanced Imaging to decline to perform MRI examinations until six weeks after the coil, filter, or stent has been placed. Bear in mind that these devices may be used by a number of medical specialists, including radiologists, cardiologists, vascular surgeons, neurosurgeons, or urologists. If you have any doubt about the presence of one of these devices, a simple X-ray of the involved body area will settle the question.
Metallic foreign bodies
Metal grinding fragments, splinters, or other metal foreign bodies within the eye
- Work history as a metal grinder or metal fabricator
- Shrapnel
- Bullets or bullet fragments
If you have any of the above listed metallic foreign bodies, shrapnel, or bullet fragments, an X-ray of the body area in question can determine the safety of the MRI examination in your particular case. Once again, please inform our staff of your concern prior to entering the MRI scanner room.
Other implants
- Some penile implants
- Some middle ear (ossicular, stapes) prostheses
- Metallic ocular or eyelid implants
- Fatio eyelid spring
- Retinal tack made from martensitic stainless steel
- Troutman magnetic ocular implant
- Unitek round wire eyelid spring
As with any question concerning the safety of a particular type of implant or prosthesis, the more detailed and reliable information we have, the better we can judge the safety of the MRI examination. Your help in securing original operative notes, exact implant type and name, and manufacturer "800 numbers" for MRI compatibility information is greatly appreciated by all of us at Albany Advanced Imaging.
Sources:
Magnetic Resonance Imaging of the Brain and Spine. Second Edition. Atlas, S. W., ed. Lippincott-Raven Publishers, Philadelphia. 1996.
Magnetic Resonance. Bioeffects, safety, and patient management. Shellock, F. G., and Kanal, E. Raven Press, New York. 1994.