Magnetic resonance imaging apparatus and magnetic resonance imaging method

A magnetic resonance imaging apparatus, comprising:

• a gradient magnetic field coil unit configured to generate a gradient magnetic field in an imaging region according to a current supplied thereto;
• a temperature measuring unit configured to perform temperature measurement of the gradient magnetic field coil unit;
• a data storing unit configured to store “a plurality of shift data which correspond to a plurality of temperature regions respectively and indicate shift of a center frequency of magnetic resonance of a hydrogen atom in the imaging region in response to temperature variation of the gradient magnetic field coil unit”;
• a pulse setting unit configured to calculate an estimated shift of the center frequency of magnetic resonance of a hydrogen atom based on “temperature shift of the gradient magnetic field coil unit indicated by the temperature measurement” and “the shift data corresponding to a temperature region including temperature of the gradient magnetic field coil unit indicated by the temperature measurement”, and correct a center frequency of an RF pulse based on the estimated shift;
• and
• an imaging unit configured to transmit the RF pulse corrected by the pulse setting unit, acquire nuclear magnetic resonance signals from an object in the imaging region, and generate image data of the object based on the nuclear magnetic resonance signals.

A magnetic resonance imaging method comprising the steps of:

• performing temperature measurement of a gradient magnetic field coil unit of a magnetic resonance apparatus;
• performing judgment as to whether temperature of the gradient magnetic field coil unit has risen or fallen, based on result of the temperature measurement;
• calculating an estimated shift of a center frequency of magnetic resonance of a hydrogen atom in an imaging region based on data corresponding to result of the judgment out of “first data corresponding to a case of temperature rise of the gradient magnetic field coil unit” and “second data corresponding to a case of temperature fall of the gradient magnetic field coil unit”, the first and second data indicating a shift of the center frequency of magnetic resonance;
• correcting a center frequency of an RF pulse based on the estimated shift;
• acquiring nuclear magnetic resonance signals from an object in the imaging region by transmitting “the RF pulse whose center frequency is corrected based on the estimated shift”
• generating image data of the object based on the nuclear magnetic resonance signals.