US 6,445,183 B1Granted

Magnetic resonance image diagnosing apparatus

AssigneeHitachi Medical Corporation

InventorsHiromichi Shimizu, Shigeru Watanabe

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Abstract

A burst wave 91 is applied as an RF magnetic filed in order to excite nuclei of hydrogen, and also a oradient magnetic field 95 along a readout direction is applied so as to excite magnetization in a stripe shape. Thereafter, while a magnetization-inverting RF magnetic field pulse 92 for selecting a slice is applied and a readout gradient magnetic field 96 is applied, a signal 97 is measured. At this time, a time instant when a spin echo is produced is made different from a time instant when a gradient magnetic field echo is produced, so that a phase rotation made by a chemical shift may be reflected on to a signal. The MR signal 97 is processed by a 2-dimensional Fourier-transform, and a phase distribution is calculated from both a real part and an imaginary part of complex data after the 2-dimensional Fourier-transform. Then, this calculated phase distribution is converted into a temperature change so as to display the temperature change. A temperature change in a diseased portion in connection with IVMR can be monitored in real time.

Claims25

Dependent claims

A magnetic resonance image diagnosing apparatus comprising:

magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a radio-frequency magnetic field in a space where an object under examination is located;
detecting means for detecting a magnetic resonance signal produced from said object under examination;
means for reconstructing an image based upon said detected magnetic resonance signal;
display means for displaying thereon an image;
and control means for controlling each of said means, wherein:
said control means executes the below-mentioned sequences, namely:
1) a burst wave for exciting nuclei of hydrogen is applied as said radio-frequency magnetic field, and at the same time, a gradient magnetic field along at least one direction is applied;
2) after said burst wave has been applied, a magnetization-inverting radio-frequency pulse is applied in combination with a slice-selecting gradient magnetic field;
3) a readout-operating gradient magnetic field is applied in such a manner that a gradient magnetic field echo is produced at such a time instant different from a time instant when a spin echo is produced by applying said radio-frequency pulse;
4) when said burst wave is applied, or said magnetic resonance signal is detected, such a gradient magnetic field which phase-encodes said magnetic resonance signal is applied;
5) the phase-encoded magnetic resonance signal is detected as the gradient magnetic field echo;
6) said detected magnetic resonance signal is Fourier-transformed, and a phase distribution is calculated based upon both a real part and an imaginary part of complex data of the Fourier-transformed magnetic resonance signal;
and
7) an image is constructed from said phase distribution, and said constructed image is displayed on said display means.

11 more elements

A magnetic resonance image diagnosing apparatus comprising:

magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a radio-frequency magnetic field in a space where an object under examination is located;
detecting means for detecting a magnetic resonance signal produced from said object under examination;
means for reconstructing an image based upon said detected magnetic resonance signal;
display means for displaying thereon an image;
and control means for controlling each of said means, wherein:
said control means executes the below-mentioned sequences, namely:
1) a burst wave for exciting nuclei of hydrogen is applied as said radio-frequency magnetic field, and at the same time, the gradient magnetic field along at least one direction among three directions is applied;
2) while a gradient magnetic field having a polarity opposite to that of said gradient magnetic field is applied as a readout-operating gradient magnetic field, a magnetic resonance signal is detected as a gradient magnetic field echo;
3) said detected magnetic resonance signal is Fourier-transformed, and a phase distribution is calculated based upon both a real part and an imaginary part of complex data of the Fourier-transformed magnetic resonance signal;
and
4) an image is constructed from said phase distribution, and said constructed image is displayed on said display means.

8 more elements

In a magnetic resonance image diagnosing apparatus comprising:

magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a radio-frequency magnetic field in a space where an object under examination is located;
detecting means for detecting a magnetic resonance signal produced from said object under examination;
means for reconstructing an image based upon said detected magnetic resonance signal;
display means for displaying thereon an image;
and control means for controlling each of said means,
said magnetic resonance image diagnosing apparatus is comprised of:
means for applying a burst wave to said object under examination so as to excite a predetermined region of said object under examination;
means for detecting a magnetic resonance signal produced by said burst wave as a gradient magnetic echo;
means for Fourier-transforming the detected magnetic resonance signal and for acquiring a phase distribution from complex data of the Fourier-transformed magnetic resonance signal;
and
means for constructing an image from said phase distribution.

8 more elements

An MR imaging method realized in a magnetic resonance image diagnosing apparatus comprising:

magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a radio-frequency magnetic field in a space where an object under examination is located;
detecting means for detecting a magnetic resonance signal produced from said object under examination;
means for reconstructing an image based upon said detected magnetic resonance signal;
display means for displaying thereon an image;
and control means for controlling each of said means, wherein:
said MR imaging method is comprised of:
1) a step in which a burst wave for exciting nuclei of hydrogen is applied as said radio-frequency magnetic field, and at the same time, a gradient magnetic field along at least one direction is applied;
2) a step in which after said burst wave has been applied, a magnetization-inverting radio-frequency pulse is applied in combination with a slice-selecting gradient magnetic field;
3) a step in which a readout-operating gradient magnetic field is applied in such a manner that a gradient magnetic field echo is produced at such a time instant different from a time instant when a spin echo is produced by applying said radio-frequency pulse;
4) a step in which when said burst wave is applied, or said magnetic resonance signal is detected, such a gradient magnetic field which phase-encodes said magnetic resonance signal is applied;
5) a step in which the phase-encoded magnetic resonance signal is detected as the gradient magnetic field echo;
6) a step in which said detected magnetic resonance signal is Fourier-transformed, and a phase distribution is calculated based upon both a real part and an imaginary part of complex data of the Fourier-transformed transformed magnetic resonance signal;
and
7) a step in which an image is constructed from said phase distribution, and said constructed image is displayed on said display means.

11 more elements

An MR imaging method realized in a magnetic resonance image diagnosing apparatus comprising:

magnetic field generating means for generating a static magnetic field, a gradient magnetic field, and a radio-frequency magnetic field in a space where an object under examination is located;
detecting means for detecting a magnetic resonance signal produced from said object under examination;
means for reconstructing an image based upon said detected magnetic resonance signal;
display means for displaying thereon an image;
and control means for controlling each of said means, wherein:
said MR imaging method is comprised of:
1) a step in which a burst wave for exciting nuclei of hydrogen is applied as said radio-frequency magnetic field, and at the same time, the gradient magnetic field along at least one direction among three directions is applied;
2) a step in which while a gradient magnetic field having a polarity opposite to that of said gradient magnetic field is applied as a readout-operating gradient magnetic field, a magnetic resonance signal is detected as a gradient magnetic field echo;
3) a step in which said detected magnetic resonance signal is Fourier-transformed, and a phase distribution is calculated based upon both a real part and an imaginary part of complex data of the Fourier-transformed magnetic resonance signal;
and
4) a step in which an image is constructed from said phase distribution, and said constructed image is displayed on said display means.

8 more elements

Dependencies are inferred from the claim text.