a low pressure return hose that allows leakage flow to return to a fluid reservoir of the driving component 103 the return hose 107 bleeds air from the lines and the cylinder internal volumes by using a virtually incompressible media e g liquid to drive the passive actuator 101 the hydraulically powered system provides many advantages over pneumatic means of generating tissue vibration for example pneumatic systems are limited by gas e g air compliance to a frequency on an order of 100 hz or less this frequency limitation limits the resolution of the mre to the imaging of smaller tissue structures a liquid fluid means of driving the application head does not have this limitation as the media used to convey flow and pressure has negligible compliance therefore higher transmitted frequencies are possible using the hydraulically powered vibration device in addition because of the virtual incompressibility of liquids the performance of the system using the hydraulically powered vibration device can be predicted with sufficient accuracy to allow the phase of the tissue vibrations to be adjusted to the phase of the applied mri which provides optimal imaging the use of virtually incompressible media also makes it possible to generate higher forces that overcome attenuation of the transmitted energy which results in the delivery of higher energies to the tissue of interest furthermore because higher power can be transmitted by liquid fluidic means flexibility in the design of the passive actuator 101 is accommodated in particular passive actuators can be implemented that transmit.