JP2001276016A5 - - Google Patents

Claims (6)

A static magnetic field generating means for generating a static magnetic field in a space in which the subject is placed; a gradient magnetic field generating means for applying gradient magnetic fields in the slice direction, phase encoding direction, and readout direction to the space; and a nucleus of the biological tissue of the subject A transmission system that irradiates a high-frequency magnetic field to cause nuclear magnetic resonance in the antenna, a reception system that detects an echo signal emitted by the nuclear magnetic resonance, and a control that controls the gradient magnetic field generating means, the transmission system, and the reception system In a magnetic resonance imaging apparatus comprising: a system; a signal processing system for performing image reconstruction calculation using an echo signal detected by a receiving system; and a means for displaying the obtained image
The control system assigns at least one of slice encoding and phase encoding to execute a two-dimensional or three-dimensional sequence, and at this time, k-space measurement points defined by at least one of the slice encoding number and the phase encoding number are set. , Share the origin, and divide into the first and second groups that are in a complex conjugate relationship with each other. In the first group, the distance from the origin to the measurement point gradually decreases in the order of measurement, and in the second group, the measurement starts from the origin. A magnetic resonance imaging apparatus characterized by controlling at least one of the gradient magnetic field generating means in the slice direction and the phase encoding direction so that the distance to a point gradually increases in the order of measurement.   The magnetic resonance imaging apparatus according to claim 1, wherein the measurement points in the k space are divided so that adjacent measurement points belong to different groups.   The magnetic resonance imaging apparatus according to claim 1, wherein at least one of the two groups divided into two includes a point that is not measured.   4. The magnetic resonance imaging apparatus according to claim 1, wherein the sum of the two divided regions is a circle, an ellipse, a sphere, or an ellipsoid inscribed in the measurement space. 5. Means for selecting and exciting a predetermined region of the subject; gradient magnetic field applying means for applying gradient magnetic fields in at least two directions to the subject; measuring means for measuring an echo signal generated from the region; and the excitation means The step of controlling the gradient magnetic field applying means and the measuring means, applying the gradient magnetic field encoded in at least two directions, and measuring the echo signal generated from the region is repeated a plurality of times while changing the intensity of the gradient magnetic field, thereby obtaining a three-dimensional image. In a magnetic resonance imaging apparatus comprising a control means for collecting data,
The control means share the origin of the measurement points in the k-space defined by the encode gradient magnetic field strengths in the two directions, have a complex conjugate relationship with each other, and adjacent lattice points belong to different groups. Dividing into the second group, the first group and the second group are measured sequentially. At that time, in the first group measured first, the distance from the origin of the k-space to the measurement point gradually decreases in the order of measurement. In the second group to be measured later, the magnetic resonance imaging apparatus performs measurement so that the distance from the origin of the k space to the measurement point gradually increases in the measurement order.   7. The magnetism according to claim 6, wherein the control unit measures only some of the measurement points in the first group and measures all the measurement points in the second group. Resonance imaging device.