A hydraulic driver of a magnetic resonance elastography (MRE) system is provided. The hydraulic driver is adapted to be connected to at least a passive actuator for contacting with a subject. The hydraulic driver includes a pump, a hydraulic piston-cylinder unit operatively coupled to the pump, and a tube assembly. The tube assembly includes a proximal end in fluid communication with the hydraulic piston-cylinder unit and a distal end in fluid communication with the passive actuator. The passive actuator oscillates in response to hydraulic energy generated in a fluid in the hydraulic driver as the pump drives the piston forward and backward in the cylinder of the hydraulic piston-cylinder unit.