Method of producing MR image and MRI system

A magnetic resonance imaging system in which an object is placed in a static magnetic field on the basis of a pulse sequence, comprising:

• means for applying to the object a one excitation RF pulse in synchronization with a pulse of slice-selective magnetic field gradient applied to the object;
• means for consecutively applying to the object a plurality of refocusing RF pulses each of which being applied in synchronization with another pulse of slice-selective magnetic field gradient applied to the object;
• and
• means for consecutively acquiring a plurality of spin echoes emanated from the object with a pulse of reading-out magnetic field gradient applied to the object, each of said plurality of spin echoes responding to each of said plurality of refocusing RF pulses and being acquired after a reading out magnetic field gradient applied to the object,
• wherein each of the acquired plurality of spin echoes is mapped in each of a plurality of blocks defined by dividing a k(Fourier)-space along a phase-encoding direction of the k-space;
• a flip angle of one specified refocusing RF pulse of the refocusing RF pulses is set to a first value equal to or less than 180.degree., said specified refocusing RF pulse being assigned for refocusing one specified spin echo of the plurality of spin echoes mapped in one specified block of the plurality of blocks, the specified block including a non-encoding location in the k-space;
• and a flip angle of the remaining refocusing RF pulse is set to a second value smaller than the first value.

A magnetic resonance imaging system in which an object is placed in a static magnetic field and imaged using a pulse sequence of fast spin echo (FSE) including a one excitation RF pulse and a plurality of refocusing RF pulses following the excitation RF pulse and generating a plurality of spin echoes, the system comprising:

• an RF coil for transmitting to the object the excitation RF pulse and the plurality of refocusing RF pulses;
• a transmitter for driving the RF coil in order to transmit the excitation RF pulse and the plurality of refocusing RF pulses;
• and
• a sequencer for controlling the transmitter on the basis of the pulse sequence wherein a flip angle of specified one of the refocusing RF pulses is set to a first value equal to or less than 180.degree. and the flip angle of remaining refocusing RF pulse is set to a second value smaller than the first value, said specified refocusing RF pulse being assigned for refocusing one of the spin echoes mapped in a divided block to be echo-mapped including a zero encoding location in a k(Fourier)-space.