Safety evaluation of MRI examination for the intraocular Ex-PRESS drainage device
NIE Li1, PAN Weihua1,
1.Department of Glaucoma, Eye Hospital of Wenzhou Medical University, Wenzhou, 325027; 2.Department of Medical Imaging, the Second Affiliated Hospital of Zhejiang University, Hangzhou, 310008
Abstract：Objective: To evaluate the safety of the intraocular Ex-PRESS glaucoma drainage device during magnetic resonance imaging (MRI). Methods: The Ex-PRESS drainage device was implanted in the anterior chamber or fixed through the corneal limbus respectively in pig eyes. Then they were exposed to magnetic field of standard 1.5T and 3.0T MRI scanning protocols. Testing included measurements of translational and rotational motion of the device induced by static magnetic field. In addition, the surrounding tissue of the device was also observed due to possible radiofrequency heating. Seven patients with Ex-PRESS drainage device implanted at the limbus were also studied. For each subject, 1.5T and 3.0T MRI scan were obtained. The safety and imaging quality were then assessed. Results: Rotation and displacement did not occur under 1.5T and 3.0T conditions in both tests. There was no obvious burn sign in the surrounding tissues of the device. For the patients, the position of the Ex-PRESS device kept stable after MRI scanning protocols. The presence of Ex-PRESS device had mild impact on visualization of the surrounding tissue. Only minimal artifact was present at the implant site. Conclusion: Routine MRI examination is safe for intraocular Ex-PRESS glaucoma drainage device implantation.
