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Metallic stents: evaluation of MR imaging safety
1Department of Radiology, School of Medicine, University of Southern California, Los Angeles 90036, USA.
Objective:
The objective of our investigation was to evaluate safety during MR imaging (i.e., magnetic field interactions, heating, and artifacts) for metallic stents.
Materials And Methods:
Different types of metallic stents were tested for magnetic field interactions, heating, and artifacts using a 1.5-T MR system. Magnetic field-related translational attraction and torque were assessed using previously described techniques. Heating was evaluated using an infrared thermometer to record temperatures immediately before and after performing MR imaging using a whole-body-averaged specific absorption rate of 1.3 W/kg. Artifacts were assessed by placing the stents inside a fluid-filled phantom and performing MR imaging using fast spoiled gradient-echo and T1-weighted spin-echo pulse sequences.
Results:
For the 10 different stents evaluated, we found no magnetic field interactions. the highest temperature change was < or = +0.3 degrees C, and the artifacts involved signal voids that would not create diagnostic problems as long as the area of interest was not positioned exactly where a particular stent was located.
Conclusion:
The findings of the safety tests indicated that the 10 different metallic stents would be safe for patients undergoing MR imaging procedures using MR systems with static magnetic fields of 1.5 T or less.