MRI compatibility and visibility assessment of implantable medical devices

We have developed a protocol to evaluate the magnetic resonance (MR) compat ibility of implantable medical devices, The testing protocol consists of th e evaluation of magnetic field-induced movement, electric current, heating, image distortion, and device operation. In addition, current induction is evaluated with a finite clement analysis simulation technique that models t he effect of radiofrequency fields on each device, The protocol has been ap plied to several implantable infusion pumps and neurostimulators with assoc iated attachments. Experiments were performed using a 1.5-T whole-body MR s ystem with parameters selected to approximate the intended clinical and wor st case configuration. The devices exhibited moderate magnetic held-induced deflection and torque but had significant image artifacts. No heating was detected for any of the devices, Pump operation was halted in the magnetic held, but resumed after removed, Exposure to the magnetic held activated so me of the neurostimulators, J, Magn, Reson, Imaging 1999;9:596-603. (C) 199 9 Wiley-Liss, Inc.