Various hemostatic vascular clips, other types of clips, fasteners, and staples evaluated for magnetic field interactions have been found to be acceptable for patients undergoing MR imaging procedures at 1.5T or less. These implants are made from nonferromagnetic materials such as tantalum, nitinol, and titanium. Some hemostatic and other similar clips are made from biodegradable materials, which do not pose a hazard to patients. Patients who have these previously tested implants (see The List) are not at risk for injury during MRI procedures. There has never been a report for the devices that have been tested of an injury to a patient in association with a hemostatic clip, other type of clip, fastener, or staple in the MRI environment. Patients with nonferromagnetic versions of these implants may undergo MR procedures immediately after the implants are placed surgically.

RESOLUTION CLIP, UNSAFE FOR MRI

The Resolution Clip (Boston Scientific Corporation) is indicated for placement within the gastrointestinal tract for the purpose of endoscopic marking or hemostasis. Currently, the Resolution Clip is labeled, as follows:"Do not perform MRI procedures on patients who have had clips placed within their gastrointestinal tract, as this could be harmful to patients."

MRI SAFETY AT 3T AND HEMOSTATIC CLIPS, OTHER CLIPS, FASTENERS, AND STAPLES

At 3T, a variety of hemostatic clips, other clips, fasteners, and staples have been evaluated for MR safety. In general, these devices do not present an additional risk to patients undergoing MR procedures. Please refer to The List for specific information.Dr. Shellock is an adjunct clinical professor of radiology and medicine at the Keck School of Medicine and director of MRI studies of Biomimetic MicroElectronic Systems (BMES) Implants, National Science Foundation BMES Engineering Research Center, University of Southern California, and Institute for Magnetic Resonance Safety, Education, and Research. www.MRIsafety.comwww.IMRSER.org

BIBLIOGRAPHY

Barrafato D, Henkelman RM. Magnetic resonance imaging and surgical clips. Can J Surg 1984;27:509-512.
Brown MA, Carden JA, Coleman RE, et al. Magnetic field effects on surgical ligation clips. Magn Reson Imaging 1987;5:443-453.
Resolution Clip information, http://www.bostonscientific.com/templatedata/imports/collateral/
Endoscopy/prospec_resolution_01_us.pdf
Shellock FG. MR imaging of metallic implants and materials: a compilation of the literature. AJR 1988;151:811-814.
Shellock FG. Biomedical implants and devices: assessment of magnetic field interactions with a 3.0-Tesla MR system. J Magn Reson Imaging 2002;16:721-732.
Shellock FG, Crues JV. High-field strength MR imaging and metallic biomedical implants: an ex vivo evaluation of deflection forces. AJR 1988;151:389-392.
Shellock FG, Morisoli S, Kanal E. MR procedures and biomedical implants, materials, and devices: 1993 update. Radiology 1993;189:587-599.
Shellock FG, Swengros-Curtis J. MR imaging and biomedical implants, materials, and devices: an updated review. Radiology 1991;180:541-550.
Shellock FG. Reference manual for Magnetic Resonance safety, implants, and devices: 2006 ed. Biomedical Research Publishing Group, Los Angeles, CA, 2006.