Resources
Recently Published Articles
The Safety Debate Surrounding MRI and Implantable Cardiac Devices
To read the articles listed on this page, click on the publication link and do a key word search for ‘MRI’.
- Luechinger R, Zeijlemaker V, Pedersen E, et al. In vivo heating of pacemaker leads during magnetic resonance imaging. Eur Heart J. 2005;26(4):376-383.
Responses to above article - Sommer T, Vahlhaus C, Lauck G, et al. MR imaging and cardiac pacemakers: In-vitro evaluation and in-vivo studies in 51 patients at 0.5 T. Radiology. 2000;215(3):869-879.
- Gimbel J. Bailey S, Tchou P, et al. Strategies for the safe magnetic resonance imaging of pacemaker-dependent patients. PACE. 2005; 28:1041-1046.
- Faris O, Shein M. Government Viewpoint: U.S. Food & Drug Administration: Pacemakers, ICDs and MRI. PACE. 2005;28:268-269.
- Stanton M. Industry Viewpoint: Medtronic: Pacemakers, ICDs, and MRI. PACE. 2005;28:265.
- Duru F, Luechinger R, Scheidegger M, et al. Pacing in magnetic resonance imaging environment: Clinical and technical consideration on compatibility. Eur Heart J. 2001;22:113-124.
- Martin E, Coman J, Shellock F, et al. Magnetic resonance imaging and cardiac pacemaker safety at 1.5-Tesla. J Am Coll Cardiol. 2004;43:1315-1324.
Responses to above article - Roguin A, Zviman M, Meininger G, et al. Modern pacemaker and implantable cardioverter/defibrillator systems can be magnetic resonance imaging safe: In vitro and in vivo assessment of safety and function at 1.5 T. Circulation. 2004;110:475-482.
Responses to above article - Leal Del Ojo J, Moya F, Villalba J, et al. Is magnetic resonance imaging safe in cardiac pacemaker recipients? PACE. 2005;28:274-278.
- Irnich W, Irnich B, Bartsch C, et al. Do we need pacemakers resistant to magnetic resonance imaging? Europace. 2005;7:353-365.
Responses to above article - Gimbel J, Bailey S, Tchou P, et al. Strategies for the safe magnetic resonance imaging of pacemaker-dependent patients. PACE. 2005;28:1-6.
- Shellock F, Fieno D, Thomson L, et al. Cardiac pacemaker: In vitro assessment at 1.5T. Am Heart J . 2006;151:436-443.
MR Tutorials
- Magnetic Resonance Imaging – MR physics, basic and advanced
- The Basics of MRI
- Basic Nuclear Magnetic Resonance – from MRI Physics Put Simply
Associations and Related Websites
American College of Radiology
American Roentgen Ray Society
American Society of Head and Neck Radiology
American Society of Neuroradiology
American Society for Testing and Materials (ASTM)
British Society of Interventional Radiology
Food and Drug Administration’s Center for Devices and Radiological Health
European Magnetic Resonance Forum (EMRF)
Institute for Magnetic Resonance Safety, Education and Research
International Society for Magnetic Resonance in Medicine (ISMRM)
MRIsafety.com
Radiological Society of North America
Society for Cardiovascular Magnetic Resonance
Glossaries
Basic MRI Glossary
Gradient Magnetic Field
A variation in the magnetic field with respect to distance. This field makes the energy status of the protons position dependent.
MR Safe
Use of the device in an MR environment presents no additional risk to the patient but quality of the image may be affected.
MR Conditional
No known hazards under specific conditions. Considered safe only when certain specific conditions are met.
MR Unsafe
Hazards posed in all MR environments. Any device not labeled MR safe or MR conditional.
Pulsed Radio Frequency (RF) Field
Changes the energy state of protons and elicits magnetic resonance signals from tissue. Frequencies used in the millions of cycles per second (MHz).
Radiopaque
Visible using standard X-ray techniques.
Specific Absorption Rate (SAR)
Measure of the absorption of electromagnetic energy in the body, measured in units of watts per kilogram (W/kg).
Static Magnetic Field
Magnetic field created by the large magnet found in MRI, used to align protons. Always present, even when scanner is not imaging. The magnetic force of attraction for a 1.5 Tesla MRI system is approximately 30,000 times stronger than the earth's magnetic field.
Tesla
Unit of measurement to determine the strength of a magnet, equal to 10,000 Gauss. The earth's magnetic field varies between 0.3 - 0.7 Gauss.
Basic Cardiac Device Glossary
Capture
Initiation of depolarization of the atria and/or ventricles by an electrical stimulus delivered by an artificial pacemaker or ICD.
Lead (or Electrode, Catheter)
Thin, insulated cable which conducts energy and carries electrical signals to and from the heart.
Implantable Cardioverter Defibrillator (ICD)
Device which terminates an erratic, life-threatening cardiac arrhythmia by delivering a high energy, direct current, electrical stimulus to cardiac tissue. An ICD is usually implanted in the upper chest or abdominal area.
Pacemaker/Implantable Pulse Generator (IPG)
Device which provides timed electrical stimuli to the heart to restore the heartbeat to a more normal rate, thereby relieving symptoms of bradycardia. A pacemaker system includes the pulse generator and the lead(s). Pacemakers are usually implanted in the pectoral region.
Programmer
A small computer used in a clinician's office to make changes in the operations of an implanted device. The programmer magnet is often placed over the pacemaker to collect information stored in the pacemaker. Note: Programmers are not labeled for use in the MR environment. Programming is performed away from the MR scanner.
Sensing
The ability of a pacemaker or ICD to recognize and respond to the electrical activity of the heart.
Slew Rate
The rate of change over time of the magnetic fields that make up the gradient fields.
Threshold (or Stimulation Threshold)
The minimum electrical stimulus needed to consistently elicit a cardiac depolarization. It is expressed in terms of amplitude (volts, milliamps) and pulse width (milliseconds), or energy (microjoules).
