Patent ID: 8362774

Claim:
A magnetic resonance imaging (MRI) apparatus comprising: a static field magnet which generates a static magnetic field; a gradient field coil, located inwardly of the static field magnet, which generates a gradient magnetic field superimposed on the static magnetic field; a cylindrical bore tube disposed inside the gradient field coil; a radio frequency coil unit, located inwardly of the bore tube leaving an annular space therebetween, which coil unit includes a cylindrical base portion having disposed thereon a first group of electronic circuit elements and a second group of electronic circuit elements within said annular space, said first and second groups of electronic circuit elements being arranged circumferentially around an outer side of the cylindrical base portion in said annular space; a first annular gas flow path which is formed in said annular space between the outer side of the cylindrical base portion and an inner side of the cylindrical bore tube in order to gas-cool the first group of electronic circuit elements; a second annular gas flow path formed in said annular space between the outer side of the cylindrical base portion and the inner side of the cylindrical bore tube, said second annular gas flow path communicating with the first annular gas flow path through at least one connecting gas flow port at which the gas flow changes direction from the first annular gas flow path into the second annular gas flow path in order to gas-cool the second group of electronic circuit elements; and a cooling unit, located external to said cylindrical base portion and external to said annular space, which gas-cools the radio frequency coil unit by generating a cooling gas flow flowing into said first annular gas flow path and from the first annular gas flow path to the second annular gas flow path.