Magnetic resonance imaging compatibility of endoclips

Background

Endoscopic clipping devices are now available for treatment of GI hemorrhage and microperforations. All commercially available endoclips are labeled as magnetic resonance imaging (MRI) incompatible. No data are available about the actual magnetic field strength at which endoclips are first deflected nor the clinical relevance of the magnetic fields on endoclips used in GI endoscopy.

Objective

To determine the compatibility of different endoclips with MRI.

Design

Prospective observational study.

Setting

Experiment on excised pig tissue in an MRI scanner.

Interventions

The physical deflection and strength of attraction of endoclips: Resolution Clip, TriClip, QuickClip, and Ethicon Endo-surgery Clip were measured in different positions by using an MRI scanner at a field strength of 1.5 Tesla. Endoclips that demonstrated deflection were attached to a pig stomach and tested for detachment at a 1.5-Tesla MRI field strength.

Main Outcome Measurements

Physical deflection and detachment from pig stomach mucosa in an MRI scanner.

Results

All endoclips except the one made by Ethicon Endo-surgery demonstrated physical deflection under the tested conditions. The magnetic attraction was strongest for the Resolution Clip (0.7 gauss) compared with the TriClip (1.2 gauss) and the QuickClip (26.8 gauss). Only the Triclip demonstrated detachment from the pig gastric tissue under testing conditions.

Limitations

A pig model and a small number of clips.

Conclusions

The Ethicon Endo-surgery clip is compatible with MRI. All other clips showed deflection in a magnetic field, but only the TriClip demonstrated detachment from gastric tissue, and hence should be considered MRI incompatible.

Abbreviations: ASTM, American Society for Testing and Materials, MRI, magnetic resonance imaging