A driver for use in applying an oscillating stress to a subject undergoing
a magnetic resonance elastography (MRE) examination includes a passive
actuator located in the bore of the magnet and in contact with the
subject. A remotely located acoustic driver produces acoustic energy in
response to an applied current and this energy is coupled therethrough a
flexible tube to the passive actuator. A movable element in the passive
actuator vibrates in response to this acoustic energy.