A recent "Sentinel Alert" from the Joint Commission addressing the prevention of accidents and injuries in the MRI suite stated: "All implants should be checked against product labeling or manufacturer literature specific to that implant, or peer-reviewed published data regarding the device or implant in question. Technologists should be provided with ready access to this information." The list posted on www.MRIsafety.com now contains information for over 1800 implants, with more than 600 tested at 3T. This database is provided in an effort to facilitate the pre-MRI patient screening process, which is conducted by MRI healthcare workers.In general, it was previously believed that since virtually all hemostatic (also called ligating) vascular clips and similar devices (including "endoclips" deployed through endoscopes) are made from nonferromagnetic materials such as tantalum, titanium, and certain forms of stainless steel, patients with these implants are not at risk for injury in association with MRI procedures. Patients with nonferromagnetic versions of these implants may undergo MRI examinations procedures immediately after they are placed. To date, for the hemostatic clips that have undergone MRI testing, there has been no patient injury or other problem related to MRI. Several new hemostatic clips in use today, however, present potential problems for patients referred for MRI procedures. Patients with these clips require special attention to ensure the safe use of MRI. In some cases, MRI is deemed unsafe. In others, a waiting period is necessary and x-rays must be inspected to determine if the clips are present or not prior to performing MRI.Specific MRI-related labeling statements for the hemostatic clips that require further attention during the pre-MRI screening procedure are the following:

RESOLUTION CLIP

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

LONG CLIP, HX-600-090L

The Long Clip HX-600-090L (Olympus Medical Systems) is indicated for placement within the gastrointestinal tract for the purpose of endoscopic marking, hemostasis, or closure of GI tract luminal perforations within 20-mm as a supplementary method. Currently, the Long Clip HX-600-090L is labeled, "Do not perform MRI procedures on patients who have clips placed within their gastrointestinal tracts. This could be harmful to the patient."Additional information:Olympus endoscopic clips have been shown to remain in the patient an average of 9.4 days, but retention is based on a variety of factors and may result in a longer retention period. Prior to MRI, the physician should confirm there are no residual clips in the GI tract. The following techniques may be used for confirmation:1. View the lesion under radiologic imaging. Olympus clip fixing devices are radiopaque. By using x-ray, the physician can determine if any residual clips are in the gastrointestinal tract. If no clips are evident under radiologic imaging, MRI may be accomplished. 2. Endoscopically examine the lesion. If no clips remain at the lesion, MRI may be accomplished.

QUICKCLIP2, HX-201LR-135 & HX-201UR-135

The QuickClip2, HX-201LR-135 & HX-201UR-135 (Olympus Medical Systems) are indicated for placement within the gastrointestinal tract for the purpose of endoscopic marking, hemostasis, or closure of GI tract luminal perforations within 20-mm as a supplementary method. Currently, the QuickClip2 (HX-201LR-135 & HX-201UR-135) is labeled, "Do not perform MRI procedures on patients who have clips placed within their gastrointestinal tracts. This could be harmful to the patient."Additional information: Olympus endoscopic clips have been shown to remain in the patient an average of 9.4 days, but retention is based on a variety of factors and may result in a longer retention period. Prior to MRI, the physician should confirm there are no residual clips in the GI tract. The following techniques may be used for confirmation:1. View the lesion under radiologic imaging. Olympus clip fixing devices are radiopaque. By using x-ray, the physician can determine if any residual clips are in the gastrointestinal tract. If no clips are evident under radiologic imaging, MRI may be accomplished. 2. Endoscopically examine the lesion. If no clips remain at the lesion, MRI may be accomplished.

QUICKCLIP2 LONG, HX-201LR-135L & HX-201UR-135L

The QuickClip2 Long, HX-201LR-135L & HX-201UR-135L (Olympus Medical Systems) are indicated for placement within the gastrointestinal tract for the purpose of endoscopic marking, hemostasis, or closure of GI tract luminal perforations within 20-mm as a supplementary method. Currently, the QuickClip2 Long (HX-201LR-135L & HX-201UR-135L) is labeled, "Do not perform MRI procedures on patients who have clips placed within their gastrointestinal tracts. This could be harmful to the patient."Additional information: Olympus endoscopic clips have been shown to remain in the patient an average of 9.4 days, but retention is based on a variety of factors and may result in a longer retention period. Prior to MRI, the physician should confirm there are no residual clips in the GI tract. The following techniques may be used for confirmation:1, View the lesion under radiologic imaging. Olympus clip fixing devices are radiopaque. By using x-ray, the physician can determine if any residual clips are in the gastrointestinal tract. If no clips are evident under radiologic imaging, MRI may be accomplished. 2. Endoscopically examine the lesion. If no clips remain at the lesion, MRI may be accomplished.

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.
http://www.jointcommission.org/SentinelEvents/SentinelEventAlert/sea_38.htm
http://mrisafety.com/
Raju GS. Endoclips for GI endoscopy. Gastrointestinal Endoscopy 2004; 59:267-279.
Resolution Clip information, http://www.bostonscientific.com/templatedata/imports/collateral/Endoscopy/prospec_resolution_01_us.pdf
Shellock FG. Reference manual for magnetic resonance safety, implants, and devices, 2008 ed. 2008, Los Angeles: Biomedical Research Publishing Group.
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.