Magnetic resonance imaging following InterStim®: an institutional experience with imaging safety and patient...

We retrospectively assessed patient safety and satisfaction after magnetic resonance imaging (MRI) in patients with an InterStim® unit.

The records of all patients implanted with InterStim® between 1998 and 2006 were reviewed. Nine of these patients underwent MRI following InterStim® implantation. The patients' neurologists requested the MRI exams for medical reasons. Both 0.6  Tesla (T) and 1.5  T machines were used. Patient safety, interference of implanted pulse generator (IPG) with radiological interpretation, and patient satisfaction were assessed in these patients.

The first patient in the series had IPG failure following MRI. For this patient, the voltage amplitude was set to zero, the IPG was turned off, and the IPG magnetic switch was left on. The patient underwent MRI uneventfully; however, the IPG did not function upon reprogramming. The IPG magnetic switch was turned off for the eight subsequent patients, all of whom underwent MRI safely. In addition, all of their IPGs functioned appropriately following reprogramming. Of the 15 MRIs performed, the lumbar spine was imaged in eight studies, the pelvis was imaged in one study, and the remaining examinations involved imaging the brain or cervical spine. Neither the IPG nor the sacral leads interfered with MRI interpretation. None of the eight patients perceived a change in perception or satisfaction following MRI.

Although we don't advocate the routine use of MRI following InterStim® implantation, our experience suggests MRI may be feasible under controlled conditions and without adverse events.