Magnetic-resonance image diagnostic apparatus and method of controlling the same

摘要

A magnetic resonance imaging diagnostic apparatus includes a generating unit which generates a slice gradient magnetic field, a phase-encode gradient magnetic field and a read-out gradient magnetic field that extend in a slice axis, a phase-encode axis and a read-out axis, respectively, a setting unit which sets a dephase amount for weighting a signal-level decrease resulting from flows in the arteries and veins present in a region of interest of a subject, with respect to at least one axis selected form the slice axis, phase-encode axis and read-out axes, and a control unit which controls the generating unit by using a pulse sequence for a gradient echo system, which includes a dephase gradient-magnetic-field pulse that corresponds to the dephase amount set by the setting unit for the at least one axis.

主权项

1. A magnetic resonance imaging (MRI) diagnostic apparatus comprising:
MRI system components including static and gradient magnetic field generators, at least one radio frequency (RF) coil coupled to an examination space within magnetic fields generated by the static and gradient magnetic field generators, an RF transmitter, an RF receiver and a control computer system connected to control other MRI system components, said control computer system including at least one computer and memory configured to controllably generate a slice gradient magnetic field, a phase-encode gradient magnetic field and a read-out gradient magnetic field that extend in a slice axis, a phase-encode axis and a read-out axis, respectively; use gradient magnetic fields to effect a gradient echo pulse sequence, which includes a dephase gradient-magnetic-field pulse in at least a selected one of the slice axis, phase-encode axis and read-out axis, the dephase gradient-magnetic field pulse being adjusted in the gradient echo pulse sequence to a dephase amount which weights a signal-level decrease resulting from flow in both arteries and veins present in a region of interest of a subject and also concurrently suppresses a signal-level decrease in surrounding background tissues of both the arteries and veins; collect magnetic resonance signals generated in the region of interest by nuclear magnetic resonance; and generate an image of the region of interest using collected magnetic resonance signals wherein image pixel values of both the arteries and veins are lower than pixel values of the background tissues as a result of said dephase amount having been used during generation of the magnetic resonance signals, wherein the imaging conditions are set such that a difference in magnetic susceptibility is weighted in the contrast of a created image to result in said created image having both emphasized flow and susceptibility.