Patent ID: 6570383
Filing Date: 2003-05-27
Classification: G01R

Abstract:
A method for magnetic resonance (MR) imaging using an inhomogeneous static magnetic field, the method comprising the steps of:providing the inhomogeneous static magnetic field to an object of interest located within an imaging volume, the inhomogeneous static magnetic field including a static gradient component oriented in a third direction: providing a pulse sequence to the imaging volume, the pulse sequence including an excitation radio frequency (RF) pulse and n refocusing RF pulses, a readout gradient pulse oriented in the third direction, a slice selection gradient pulse oriented in the third direction, a first phase-encoding gradient pulse oriented in a first direction, and a second phase-encoding gradient pulse oriented in a second direction, wherein the first phase-encoding gradient pulse includes a first pre-phasing gradient pulse followed by a first rewinding gradient pulse, and the second phase-encoding gradient pulse includes a second pre-phasing gradient pulse followed by a second rewinding gradient pulse and wherein an integral of the first pre-phasing gradient pulse is equal and opposite in sign to an integral of the first rewinding gradient pulse within a time period between any adjacent refocusing RF pulses, and an integral of the second pre-phasing gradient pulse is equal and opposite in sign to an integral of the second rewinding gradient pulse within the time period between any adjacent refocusing RF pulses; and acquiring a plurality of echo signals emitted from the object of interest located within the imaging volume per excitation of the pulse sequence, wherein acquiring a plurality of echo signals includes acquiring n lines of k-space data, one line of k-space data for each one of the n refocusing RF pulses; wherein an integral of the readout gradient pulse between the excitation RF pulse and a first refocusing RF pulse is half the value of an integral of the readout gradient pulse between any two refocusing RF pulses and wherein the static gradient component comprises the readout gradient pulse and the slice selection gradient pulse.