Patent ID: 7518362

Claim:
A magnetic resonance imaging system comprising: means for generating a static magnetic field; gradient magnetic field generating means for generating a gradient magnetic field; RF magnetic field generating means for generating an RF magnetic field; measuring means for measuring a magnetic resonance signal generated from a target; computing means configured to perform a computation on the magnetic resonance signal; memory means for storing the magnetic resonance signal and the result of computation by the computing means; and sequence control means configured to set operating conditions to respective portions of the gradient magnetic field generating means, the RF magnetic field generating means, the measuring means, the computing means and the memory means; said sequence control means being configured to: (1) measure a first magnetic resonance signal generated from a measurement voxel at the magnetic resonance spectrum measurement at a first time interval, (2) detect a magnetic resonant frequency F 1 of water from a first magnetic resonance spectrum obtained by Fourier-transforming the first magnetic resonance signal, (3) measure a second magnetic resonance signal generated from the voxel at a second time interval subsequent to the elapse of a predetermined time from the measurement of the first magnetic resonance signal, (4) detect a magnetic resonant frequency F 2 of water from a second magnetic resonance spectrum obtained by Fourier-transforming the second magnetic resonance signal, (5) calculate a time-varying rate of the magnetic resonant frequency of water based on the detected F 1 and detected F 2 , (6) set, based on the calculated time-varying rate of the magnetic resonant frequency of water, a transmission frequency of the RF magnetic field radiated into the target or/and a received frequency, and (7) measure a magnetic resonance signal a predetermined number of times using the set transmission frequency of the RF magnetic field and/or the set received frequency.