Magnetic resonance imaging system

A magnetic resonance imaging system comprising:

• static magnetic field application means for applying a uniform static magnetic field to an object to be examined;
• excitation means for applying a radio-frequency magnetic field for exciting a magnetic resonance phenomenon to said object to be examined;
• gradient field application means for applying, to said object to be examined, a first gradient field which has a magnetic gradient along a first direction and is used for determining a slice to be imaged in which the magnetic resonance phenomenon is excited, a second gradient field which has a magnetic gradient along a second direction perpendicular to the first direction and is used for phase-encoding echo data based on the magnetic resonance phenomenon, and a third gradient field which has a magnetic gradient along a third direction perpendicular to the first and second directions, and is used for reading out the echo data based on the magnetic resonance phenomenon;
• control means for controlling said excitation means and said gradient field application means so as to apply the pulsed radio-frequency magnetic field and the pulsed first to third gradient fields in accordance with a predetermined sequence;
• signal acquisition means for acquiring an echo signal based on the magnetic resonance phenomenon generated in the object to be examined;
• and image reconstruction means for obtaining an image of magnetic resonance data from the echo signal, said control means comprising
• first echo control means for alternately and repetitively executing a first operation for applying the third gradient field while repetitively inverting it so as to produce the echo signal, and a second operation for applying, as the radio-frequency magnetic field, a 180.degree. pulse which can compensate for an echo signal phase error due to a nonuniformity and offset of the static magnetic field so as to generate the echo signal, and
• second echo control means for inverting the second gradient field each time the 180.degree. pulse is applied.