Multiple-coil adopting a quadrature detection method applied thereto and a signal processing circuit employing the same in an MRI apparatus in a vertical magnetic system

Claim 1

An RF probe for an MRI apparatus in a vertical magnetic field system, comprising: (a) an array coil comprising a plurality of unit coils which are arranged in a direction perpendicular to a direction of a static magnetic field, for detecting an RF magnetic field in another direction perpendicular to the direction of the static magnetic field, each of said unit coils detecting the RF magnetic field independently of one another, and said array coil being arranged so that a mutual coupling between the adjacent unit coils become a minimum; (b) a compensating coil which detects an RF magnetic field in a direction perpendicular to both a direction of the RF magnetic field detected by said array coil and said direction of said static magnetic field; (c) first receiving means for receiving a signal detected by said array coil; (d) second receiving means for receiving a signal detected by said compensating coil; (e) phase adjusting means for adjusting a phase of a first signal, which is obtained as an output of said first receiving means, and a phase of a second signal, which is obtained as an output of said second receiving means, to a predetermined relationship; (f) first gain adjusting means for adjusting a gain of said first signal; (g) second gain adjusting means for adjusting a gain of said second signal; and (h) means for combining said first signal and said second signal.