MRI embodiments for controlling an arrangement order of multiple echoes in a k-space

1. A magnetic resonance imaging apparatus comprising:

a high frequency magnetic field generating unit to generate a high-frequency magnetic field in a static magnetic field space;

a gradient magnetic field generating unit to generate a gradient magnetic field in the static magnetic field space;

a reception unit to receive a nuclear magnetic resonance signal generated from an examination target placed in the static magnetic field space;

a control unit to control the high-frequency magnetic field generating unit, the gradient magnetic field generating unit and the reception unit, to execute a pulse sequence of the fast spin echo method that collects multiple echoes using a spin flip after a single RF excitation, and to control an arrangement order in a k-space where the multiple echoes are arranged based on phase characteristics of the multiple echoes collected after the single RF excitation; and

a phase calculation unit to calculate, as the phase characteristics, phase differences between a reference phase and phases of the multiple echoes, and to determine the arrangement order according to the phase differences;

wherein the control unit arranges the multiple echoes measured in the pulse sequence of the fast spin echo method in the k-space, according to the arrangement order determined by the phase calculation unit.

2. The magnetic resonance imaging apparatus according to claim 1 , comprising:

a pre-measurement unit to measure the phase characteristics of the multiple echoes.

3. The magnetic resonance imaging apparatus according to claim 2 , comprising:

the phase calculation unit determines the arrangement order in the ascending order of the phase differences.

4. The magnetic resonance imaging apparatus according to claim 3 ,

wherein the control unit disposes an echo to be collected first after the single RF excitation in a center of the k-space or a position close to the center, and arranges second and subsequent echoes in the k-space according to the arrangement order determined by the phase calculation unit.

5. The magnetic resonance imaging apparatus according to claim 3 ,

wherein the reference phase is a phase value of an echo collected first after the single RF excitation.

6. The magnetic resonance imaging apparatus according to claim 3 , wherein the reference phase is an average value of phases of multiple echoes collected after the single RF excitation.

7. The magnetic resonance imaging apparatus according to claim 1 ,

wherein the control unit uses phase characteristics of echoes collected at odd-number orders and echoes collected at even-number orders after the single RF excitation, to control the arrangement order.

8. The magnetic resonance imaging apparatus according to claim 7 ,

wherein the control unit arranges, of the echoes collected at odd number orders and the echoes collected at even-number orders, ones in a first region that includes the center of a k-space, and the others in a second region that is located on a high-frequency side of the first region.

9. The magnetic resonance imaging apparatus according to claim 1 ,

wherein a pulse sequence of the fast spin echo method includes at least one of a 2D pulse sequence, a 3D pulse sequence, and radial pulse sequence.

10. The magnetic resonance imaging apparatus according to claim 1 ,

wherein the control unit has a user interface unit to receive a command from a user, and the user interface unit has a control/uncontrol selection unit that enables a user to select whether to control a k-space arrangement order by the control unit.

11. The magnetic resonance imaging apparatus according to claim 10 ,

wherein the user interface unit has a phase-characteristics selection unit to select whether to use a specified value or whether to use phase characteristics obtained by pre-measurement, as phase characteristics of the multiple echoes.

12. The magnetic resonance imaging apparatus according to claim 1 ,

wherein the control unit controls an application amount of a phase-encoding gradient magnetic field to control an arrangement order of echoes in the k-space.

13. A magnetic resonance imaging method in a magnetic resonance imaging apparatus imaging using a pulse sequence of the fast spin echo method that collects multiple echoes using a spin flip after a single RF excitation, the method comprising:

generating a high-frequency magnetic field in a static magnetic field space, via a high frequency field generating unit;

generating a gradient magnetic field in the static magnetic field space, via a gradient magnetic field generating unit;

receiving a nuclear magnetic resonance signal generated from an examination target placed in the static magnetic field space, via a reception unit;

controlling the high-frequency magnetic field generating unit, the gradient magnetic field generating unit and the reception unit, via a control unit, to execute a pulse sequence of the fast spin echo method that collects multiple echoes using a spin flip after a single RF excitation, and to control an arrangement order in a k-space where the multiple echoes are arranged based on phase characteristics of the multiple echoes collected after the single RF excitation; and

calculating, as the phase characteristics, phase differences between a reference phase and phases of the multiple echoes, and determining the arrangement order according to the phase differences;

wherein the controlling arranges the multiple echoes measured in the pulse sequence of the fast spin echo method in the k-space, according to the arrangement order determined by the determining.