Safety of active implantable devices during MRI examinations: a finite element analysis of an implantable pump

IEEE Trans Biomed Eng. 2007 Apr;54(4):726-33. doi: 10.1109/TBME.2006.890145.

Abstract

The goal of this study was to propose a general numerical analysis methodology to evaluate the magnetic resonance imaging (MRI)-safety of active implants. Numerical models based on the finite element (FE) technique were used to estimate if the normal operation of an active device was altered during MRI imaging. An active implanted pump was chosen to illustrate the method. A set of controlled experiments were proposed and performed to validate the numerical model. The calculated induced voltages in the important electronic components of the device showed dependence with the MRI field strength. For the MRI radiofrequency fields, significant induced voltages of up to 20 V were calculated for a 0.3T field-strength MRI. For the 1.5 and 3.0OT MRIs, the calculated voltages were insignificant. On the other hand, induced voltages up to 11 V were calculated in the critical electronic components for the 3.0T MRI due to the gradient fields. Values obtained in this work reflect to the worst case situation which is virtually impossible to achieve in normal scanning situations. Since the calculated voltages may be removed by appropriate protection circuits, no critical problems affecting the normal operation of the pump were identified. This study showed that the proposed methodology helps the identification of the possible incompatibilities between active implants and MR imaging, and can be used to aid the design of critical electronic systems to ensure MRI-safety.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Burns / etiology
  • Burns / physiopathology*
  • Computer Simulation
  • Equipment Failure Analysis / methods*
  • Equipment Failure*
  • Equipment Safety
  • Finite Element Analysis
  • Foreign-Body Reaction / etiology
  • Foreign-Body Reaction / physiopathology*
  • Humans
  • Infusion Pumps, Implantable / adverse effects*
  • Magnetic Resonance Imaging / adverse effects*
  • Models, Biological*
  • Prostheses and Implants / adverse effects
  • Risk Assessment / methods
  • Risk Factors