Pneumatic and Hydraulic MRI-Compatible Micromanipulator System and Its MRI-Compatibility

Wong, Kahngee ;   Koseki, Yoshihiko ;   Yamauchi, Yasushi

 This paper presents a micromanipulator system designed for use in magnetic resonance imaging (MRI) environments in order to enable both micro-scale operations and functional imaging in biological animal studies. The system uses pneumatic and hydraulic actuators and non-metallic materials to ensure MRI-compatibility.  The microhand can precisely manipulate (move, cut, puncture) micron-scale objects by means of 6 hydraulic linear actuators. The microstage moves microhand and the microscope relative to the target object. The microstage has 4 linear DOF (x, y, z, m), each of which is constructed with a rotary pneumatic motor and linear screw. The microscope has 10,000 micro-optical fibers and enables real-time observation for performing manipulations.The manipulator and microstage are respectively driven by hydraulic and pneumatic pressure supplied at a distance from the outside of MRI. MRI-compatibility was tested by comparing images of a phantom with and without the microstage. The phantom is water which comprised in an acrylic container with test patterns.And the results show even though the microstage was actuated during MRI imaging, the images were not distorted or degraded, any significant deference between both images was not observed. The signal-to-noise ratio (SNR) of both images was almost equivalent with and without actuation. These results demonstrate that the system has high MRI-compatibility.