Patent ID: 7304478

Claim:
A magnetic resonance imaging apparatus comprising: a super-conducting magnet including a super-conducting coil circuit having a super-conducting coil and a permanent current switch for controlling a permanent current flowing through the super-conducting coil and a heater element for controlling demagnetization of the super-conducting coil or a sensor element for measuring amount of liquid helium which are accommodated in a helium vessel, a control circuit or a monitor circuit which is electrically connected to the heater element or the sensor element and disposed at the outside of the helium vessel, a gradient magnetic field generating means for generating a gradient magnetic field and providing the same to a static magnetic field generated by the super-conducting magnet, a high frequency magnetic field generating means for generating a high frequency magnetic field to be applied to a subject and a shielded examination room which accommodates the super-conducting magnet. characterized, in that the magnetic resonance imaging apparatus further comprises means for interrupting formation of a closed loop circuit passing through the control circuit or the monitor circuit and the super-conducting coil circuit and being provided inside the shielded examination room between the superconducting magnet and the control circuit or monitor circuit.