These materials include Ferromagnetic metal (ie, containing iron) Magnetically activated or electronically controlled medical devices (eg, pacemakers, implantable cardioverter defibrillators, cochlear implants) Nonferromagnetic electrical wires or materials (eg, pacemaker wires, certain pulmonary artery catheters) Ferromagnetic material may be displaced by the strong magnetic field, injuring a nearby organ; for example, displacement of vascular clips can result in hemorrhage.