US 5,115,812 AGranted

Magnetic resonance imaging method for moving object

AssigneeHitachi, Ltd.

InventorsKoichi Sano, Akira Maeda, Tetsuo Yokoyama, Hideaki Koizumi

Life of this patent

Estimating the term…

Loading patent…

Abstract

To obtain a high quality image at a vascular area at high speed: (1) there is used a pulse sequence which includes a bipolar phase encoding magnetic field, dephases a stationary area, and does not generate the first order moment; (2) phase distortions are estimated from measured data and removed, without incorporating a new function for function fitting; and (3) the relationship between the application timing of a readout gradient magnetic field and the latest application time of the other slice selection and phase encoding magnetic fields is obtained using as its parameter the time T.sub.E from excitation to generation of an echo peak within a measurement signal, and using this relationship, the application timing T.sub.E is obtained which makes minimum the echo peak shift quantity.

Claims9

Dependent claims

A magnetic resonance imaging method for a moving object comprising the steps of:

exciting spins within a particular area of an object to be detected;
applying a bipolar phase encoding magnetic field including a phase encoding magnetic field for giving the spins a phase shift and an inverted phase encoding magnetic field having an inverted polarity and a same amplitude of the phase encoding magnetic field, the inverted phase encoding magnetic field being applied after the phase encoding magnetic field;
measuring a one-dimensional echo signal while applying a readout gradient magnetic field;
measuring a two-dimensional echo signal by repeating the step of exciting to the step of measuring the one-dimensional echo signal while applying the bipolar phase encoding magnetic field such that at least one of the amplitude and application time of the bipolar phase magnetic field is changed at each application so as to generate a desired encoding quantity and to make the first order moment of a gradient magnetic field generated by the bipolar phase encoding magnetic field zero;
and
reproducing an image by using the measured two-dimensional echo signal.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/441,972Filed 28 Nov 1989
Priority: JP 63-30049030 Nov 1988
Granted: 26 May 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01R 33/56316
Characterization of motion or flow; Dynamic imaging: involving phase contrast techniques
G01R 33/56509
Correction of image distortions, e.g. due to magnetic field inhomogeneities: due to motion, displacement or flow, e.g. gradient moment nulling
G01R 33/56563
Correction of image distortions, e.g. due to magnetic field inhomogeneities: caused by a distortion of the main magnetic field B0, e.g. temporal…
G01R
Measuring electric variables